Polymorph for stealth

[Chronos]

I'm helping a friend optimize his Hide and Move Silently checks for his Arcane Trickster, and he already has most of the bonuses available given the books we're using. But one thing he is not yet using to boost his stealth is Polymorph and its kin. From a quick skim through the Monster Manual, the best I can find is the rat, which gives a +4 racial bonus to Hide and Move Silently, +8 Hide from size, and a 15 Dex, for a total of +10/+6, but surely there's something better elsewhere.

While we're at it, are there any humanoid forms (for use with Alter Self) that are any better than goblins? I know about whisper gnomes and Slight Build kobolds, of course, but unfortunately we're not using any of the Races Of books. I think all of the Monster Manuals are theoretically allowed, but I don't think anyone at the table has a copy of MM4 or MM5.

[Forrestfire]

Well, slight build kobold is an online thing (http://www.wizards.com/default.asp?x=dnd/we/20060420a), not technically from the races book. Not sure if that matters at all, but I'd like to throw it out there anyway.

[Karnith]

Can you use Fiend Folio? Dark Creepers (p. 38) are humanoids that get a +8 racial bonus to Hide and a +4 bonus to Move Silently checks when in shadowy areas and are Small, this leaving them with total modifiers of +12/+4 in shadowy areas, which is not bad for an Alter Self form.

Splinterwaifs (MMIII, pp. 164-165) are Medium Fey with Dex 20 and a +10 racial bonus to Hide checks, giving them +15/+5.

Also, don't rats give you +14 (+8 size, +4 racial, +2 Dex) to Hide checks?

[Chronos]

Also, don't rats give you +14 (+8 size, +4 racial, +2 Dex) to Hide checks?
Yeah, math error on my part. I think I overlooked the racial when I added it up.

Splinterwaif isn't quite as good as the rat purely on stealth, it looks like, but it might still be better overall, for having usable hands and voice. That's one to remember.

And I don't think Fiend Folio is available, though we can ask the DM. The allowed book list is Core and the sequels to Core (PHB2, DMG2, and the other Monster Manuals) and the first four Completes, but I don't think any of those have any monsters other than the Monster Manuals.

[Emperor Tippy]

Are you just trying to optimize Hide and Move Silently or are you actually just trying to be as stealthy as possible?

And what level and resources are available?

Anyways, a Toad has +12 from size, +4 racial, and +1 Dex for +17 total.

The thing is, you don't always need to actually hide. Use Mind Blank to hide from divination's that detect magic and most people will overlook a sparrow, a cat, a toad, or the like. Even if you are spotted, so long as you aren't doing anything too egregious you should pass by unremarked.

[Chronos]

The obvious possibility occurred to me last night: Are there stats anywhere for a chameleon? There must be, but unfortunately it's really difficult to search for them, since there's also (at least) a prestige class, a psionic power, and a template named that.

[Karnith]

The obvious possibility occurred to me last night: Are there stats anywhere for a chameleon? There must be, but unfortunately it's really difficult to search for them, since there's also (at least) a prestige class, a psionic power, and a template named that.
Stats for a chameleon are likely represented by the generic lizard (http://www.d20srd.org/srd/monsters/lizard.htm), unfortunately.

There could be a chameleon stat block somewhere, though, I suppose.

[Story]

They aren't even particularly good at camouflage. Certain types of octopus are however.

Of course this is fantasy, so you can do whatever you want.