I dunno, Bardic Knowledge and Inspire Courage bonuses would fit (even if noone used them). But he probably took (at least) eight levels of Factotum in there somewhere and was probably finishing Sublime Chord (or at least its casting) pre-epic. That might even be possible, but I don't have CArc to find the relevant prerequisites for Sublime Chord (that is the accelerated casting PrC, right?).