Fresh off the press from my good friend Solara over on the mmx boards:

ATHENAEUM CAT

"SHH! This is a place of learning! HEY, YOU, THIEF! DROP THAT BOOK!"

Athenaeum Cats act as both librarians, collecting and caring for books and other knowledge sources, and acquirers, seeking out and collecting sources of knowledge for their collections.

BECOMING AN ATHENAEUM CAT
Levels in cat burglar and archivist are required. Most Athenaeum Cats are obsessed with obscure sorts of knowledge, the kind that can only be found in dusty, trap-ridden dungeons or the archives of unfriendly magic-users.

ENTRY REQUIREMENTS
Class Abilities: Kitty Form, Dark Knowledge, Lore Mastery (history, local, or nobility and royalty)
Skills: Knowledge (any two) 8 ranks, Spellcraft 8 ranks, Profession (librarian) 8 ranks
Feats: Kitty Knowledge, Spell Focus (divination)
Spells: Ability to cast 2nd level divine spells, ability to prepare and cast four divination spells of at least 2nd level


Class Skills
The Athenaeum Cat's class skills (and the key ability for each skill) are Appraise (Int), Bluff (Cha), Diplomacy (Cha), Gather Information (Cha), Hide (Dex), Knowledge (all) (Int), Listen (Wis), Move Silently (Dex), Open Lock (Dex), Profession (Int), Search (Int), Sense Motive (Wis), Spot (Wis), and Use Magic Device (Cha).
Skills Points at Each Level : 6 + int

Hit Dice: d6

Code:
   BAB     Fort     Ref    Will    Abilities                                                     Spellcasting
1.  +0       +0     +0       +2    Smarty Cat, Divination Spell Power +1                         +1 level of existing divine spellcasting class
2.  +1       +0     +0       +3    Dark Knowledge (Puissance)                                    +1 level of existing divine spellcasting class
3.  +1       +1     +1       +3    It Belongs in a Musuem!                                       +1 level of existing divine spellcasting class
4.  +2       +1     +1       +4    Kitty Memory, Divination Spell Power +2                       +1 level of existing divine spellcasting class
5.  +2       +1     +1       +4    Dark Knowledge (Foe), Talented Archivist                      +1 level of existing divine spellcasting class
6.  +3       +2     +2       +5    A Cat Always Knows                                            +1 level of existing divine spellcasting class
7.  +3       +2     +2       +5    Magic of Knowledge, Divination Spell Power +3                 +1 level of existing divine spellcasting class
8.  +4       +2     +2       +6    Magickal Kitty                                                +1 level of existing divine spellcasting class
9.  +4       +3     +3       +6    Dark Knowledge (dread secret), Effortless Sight               +1 level of existing divine spellcasting class
10. +5       +3     +3       +7    Divination Spell Power +4                                     +1 level of existing divine spellcasting class
Weapon Proficiencies: An Athenaeum Cat gains no new weapon or armor proficiencies.

Smarty Cat: Levels in this prestige class stack with your Archivist level to determine the number of times per day you can use your Dark Knowledge ability.

Divination Spell Power: At 1st, 4th, 7th, and 10th level you gain a +1 bonus to caster level on divination spells. You may also add a new divination spell of a level you can cast to your prayerbook each time you gain this class feature.

Dark Knowledge (puissance): As the Archivist ability, gained at 2nd level.

It Belongs in a Musuem!: At third level, you gain the ability to stash away your goodies, especially those that belong in a museum. By using a standard action, you can hide an item tied to knowledge or with historical significance, instantly teleporting it to an extradimensional space connected to (but not part of) your library. You can hide a number of items equal to your level in this prestige class + your intelligence modifier in this manner. You can retrieve these items as if they were stored within a bag of holding.

Kitty Memory: At fourth level, you can memorize any piece of information you choose. When you come across a piece of information (such as a passage from a book, a spell in a scroll, or a story) that you wish to remember, you can make a concentration check (DC is 10 + 1 for each piece of information you have already memorized). You can recall a piece of information you already memorized with perfect accuracy at a later date. Memorizing magical text through this ability does not give you the ability learn the spell or use the magic preserved in the text.

Dark Knowledge (foe): As the Archivist ability, gained at 5th level.

Talented Archivist: You gain a new Kitty Magic or Burglaring ability, adding your levels in this prestige class to your cat burglar and archivist levels to determine the ability you can choose.

A Cat Always Knows: At sixth level, you are treated as if the spell Arcane Sight were always affecting you. You can intensify this ability by making a DC 25 Concentration check and concentrating on an item for one minute. This acts as the identify spell, but without the material component, and it works on artifacts.

Magic of Knowledge: At seventh level, you gain the ability to use the magic inherent in information. You gain a +1 bonus to caster level for every three items you have memorized using your "Kitty Memory" class feature, up to a maximum of half your hit dice.

Magickal Kitty: At eight level, when you memorize magical text with your "Kitty Memory" class feature, you can use the "Scribe Scroll" feat to reproduce the text in scroll form, without XP lost but with the GP cost. However, because you must use strange notations when translating magic from your memory to a usable form, only you can use or read this scroll. If you use "Kitty Memory" to memorize information not translatable to text (such as the contents of a psionic tattoo) then you still produce a text, but to use it as a scroll you must succeed on a Concentration check (DC is 15+3*effective minimum caster level of information being translated) or even you cannot understand its convoluted form.

Effortless Sight: At ninth level, you gain the ability to ignore any verbal, somatic, and material components costing less than 100gp of divination spells you cast.

Dark Knowledge (dread secret): At ninth level, you gain this ability, as the Archivist ability.



PLAYING AN ATHENAEUM CAT
Athenaeum Cats are a rare and reclusive bunch, but many a would-be thief has unwittingly encountered an Athenaeum Cat when trying to steal from her library. Their curious and reclusive nature means that Athenaeum Cats often stumble across dangerous pieces of information; those who know an Athenaeum Cat generally either want to help protect her library's contents from misuse or to misuse those contents themselves.
Combat: You aren't much of a fighter, preferring to avoid conflict in your kitty form or wait for fights to resolve themselves and slink away with your treasures. You probably tried picking up a sword and helping out once, and ended up hitting yourself in the foot.
Advancement: You're either a daring treasure thief who takes knowledge from those who would misuse it or a reclusive librarian who protects knowledge from misuse and identifies what knowledge is at risk of misues. The more daring bunch tend to concentrate on cat burglar levels or other levels that let you run in and out undetected; the protectors and identifiers of knowledge are far more likely to concentrate on archivist levels.
Resources: In some especially civilized areas, Athenaeum Cats might form a guild along with like-minded individuals, pretending to be ordinary librarians and keepers of knowledge. In less civilized areas, Athenaeum Cats tend to cultivate friendships with adventurers who can protect them and their knowledge with more than just wit and spell; in any event, only a very few Athenaeum Cats reveal the extent of their abilities to others, and even fewer venture forth alone, without a fighter to beat the baddies away.

KEYBOARD CATS IN THE WORLD
"Where'd my book go? I need it before we can start ending the world."
You generally hide your abilities from others, choosing to either present yourself as a rather incompetent but surprisingly clever thief or a scholar obsessed with obscure subjects but generally handy to have around.
Daily Life: Much of your time is spent reading and categorizing your collection, but when someone tells a rumor of an ancient artifact in a tomb 2,000 miles away, you're the cat they idly pet as they tell the tale.
Notables:
Organizations: You might belong to a Guild, if you're in a particularly civilized and scholarly area. You generally aren't stupid enough to try and do what you do alone, much less in a group that fully understands your abilities, unless they all have the same passion for protecting knowledge that you do.

NPC Reaction
People don't really know what to make of you - they think you're either the worst, clumsiest thief around, or that you're a scholarly recluse who knows something about everything and who shares information in return for more information.

KEYBOARD CATS IN THE GAME
This class plays well with most parties, unless they're the conquer-the-world or start-the-apocalypse type.
Adaptation: This is meant for somewhat silly campaigns, but can play well in a more serious millieu.
Encounters: Athenaeum Cats are generally found wherever there's a concentration of knowledge or an artifact that could change/end/restart the world. They're there when said artifacts are being designed, too.

New Kitty Feats

Kitty Knowledge
You are an unusually scholarly kitty.
Prerequisites: Dark Knowledge, Kitty Form, Know(any) 6 ranks
Benefit: Your Cat Burglar and Archivist levels stack for the number of times per day you can use Dark Knowledge. Your Cat Powah ability depends on your Intelligence modifier instead of your Charisma modifier.

New Kitty Magic

Reading Cat: You gain the ability to read information with unusual speed. You can learn and comprehend written information with twice the normal speed. At fifth cat burglar level, this speed doubles again, to four times the normal speed. At tenth level, you can instantly comprehend the text of a book or another written information source with a touch. To do so, you must make a DC 20 Concentration check.