You don't even need a variant class for this, do you? Aren't there a few feats that will allow you to use your music for other things? Let me grab the Complete series, they seem to have a few I think. Hang on....
Lyric Spell in Complete Adventurer allows you to trade bardic music for extra spells. If you couple that with the Extra Music feat from the same book, you'd have 10 uses of bardic music at level 6. That would translate into 3 extra 2nd level spells and 1 extra cantrip, per day. Or 2 extra 3rd level spells and 1 extra 1st level spell. Not bad.
Ironskin Chant (same book) lets you trade 1 use of bardic music for a round of damage reduction of 5/-
Chant of Fortitude (same book) lets you trade 1 use of bardic music to grant you & your allies the Diehard feat for a round (this keeps people alive even after going below zero hit points). Because you could use & reuse this every round until you run out of bardic music slots, that's pretty handy. In addition, it's an immediate action, which I believe means you can turn it on even when it's not your turn. Ally gets struck for too much damage? You can interrupt the DM to turn it on and your ally stays up.
From Complete Mage, there is the Captivating Melody feat. It lets you expend bardic music to increase the save DC of an enchantment or illusion spell. I don't like that feat much because there is a chance that it won't work but still cost you the bardic music. Nonetheless, it is an alternative to actually using the bardic music as intended.
There might be more, but that's all I could find. I don't own Complete Scoundrel, Complete Champion, or Complete Psionic. Perhaps there might be other feats in those.