Specialized arcane casting

[Sherishade]

Ok so I debated where I should post this for a while and figured it was best here because it is homebrew whether rules or class. So I like highly specialized chars sacrificing utility for power. With this in mind I like a lot of caster prestige classes for their abilities but I hate losing full casting; I know story of every mages life.

So my first question is would you allow a mage to sacrifice one or more schools to get full casting in a class that doesn't give full casting. For example Master Transmorgrifist, Mind Binder and Demonologist, these give half or no casting but if I sacrificed one or more schools when I entered the class would that be acceptable to give full casting.

Second question will require more work that I'll undertake later but to put it simply, would creating a specialized base class similar to the beguiler be appropriate, depending upon power scaling.

[Xerlith]

In my opinion full casting is better than losing access to a school. I think it's okay if it's a heavy tradeoff.

"Alternatively, you can choose two (two?) schools. If you do, this class progresses your spells known, spells per day and caster level on every level, but only for those chosen schools"

It's wonky but it works. Like that?

[Viros]

I'd allow a player to ban one school per casting level lost, with the option to only ban a few schools and accept partial casting. In this way, certain PrC's with useful traits could still allow players to get 9th level spells. For example, if you had a half-progression class you'd normally lose five casting levels, but by giving up two schools you could just barely eke out 9th's.

This would be helpful to more flavorful themed casters, who would be able to power up interesting but weak PrC's by banning schools of magic that don't match their theme.

[Sherishade]

Thanks for the advice I'm working on two base classes similiar to the beguiler and dread necromancer in terms of embodying a specialization i'll post them when i'm done.