I was thinking, the spellsword prestige class learns how to cast magic without armor, and outside of layonara there is the war wizard in the dragonlance campaign setting.
Could there be a feat to knock off arcane spell failure? I mean if the wizard took the time to practise it it should be plausable. prerequisite: spellcraft like 7-9 ranks because you should have a decent grasp on magic before attempting it. And it should stack, like for each feat taken in it, it takes off 5% spell failure.