I am certain that some time last year I ran across an ability that lets a wizard split up his spell slots - so he could drop a lvl3 slot, and pick up 3 lvl1 slots, for instance. Not sure if it worked the other way. I think (I hope?) it was a feat, but it might have been a class ability somewhere.
Does this ring a bell for anyone? I'm having trouble running it down, and figure it's probably safer and faster to ask the community than to start cracking each book in turn... Thanks.
(Feel free to drop any other suggestions for spell flexibility feats in here - I'm playing an Ultimate Magus Wizard/Knight of the Weave at 11th level, with Extend, Maximize (modded to +2) and Residual as my metamagics. My main spells are lesser orb of fire, alter self, bright worms, mass fly and invisibility sphere.)