Shadowcaster balance

[Dhavaer]

There have been a few good ideas on how to balance the Shadowcaster, my favourite of which was giving it a Tome of Battle-style recovery system. On reading the Tome of Magic more closely, I found the Tenebrous Cabal, a shadow magic based organisation with some incredible membership benefits, the primary ones being that the Cabal loans you 1000gp per character level worth of magic items, and will sell you any item with a mystery pre-req at half price.
Would giving the Tenebrous Cabal benefits to Shadowcasters put them on the level of more balanced classes? Can free shinies make up for somewhat lackluster class features?

[Bag_of_Holding]

While that would be a huge boon to any shadowcasters, but in my opinion, what they really need is an expanded list of mysteries. I'm thinking of something akin to Arcane Disciple feat, but Cha-based. This feat (or a class feature even?) will allow a shadowcaster to pick one arcane spell of each spell level and cast them as though they were mysteries.

[Nebo_]

Can free shinies make up for somewhat lackluster class features?

I don't think so.

The best fix I've seen for the Shadowcaster is to make the mysteries per encounter.

[Dhavaer]

The best fix I've seen for the Shadowcaster is to make the mysteries per encounter.

That's my one, although someone may have came up with it before me.