[sblock]No, no feat. That would be one heck of a broken feat. There is a feat that lets you add Cha to will saves, but it only works against mind-affecting spells, so I consider it a waste. Paladin, prestige paladin, and paladin-like PrCs are pretty much the only way to get Cha mod to saves. Sadly, prestige paladin is UA and thus banned here, and Blackguard, Knight of the Crown, etc. do not advance existing casting. Warpriest has special abilities that work off Cha, but only 1/2 casting progression.
If all you want is for Cha to be useful, consider taking one of the feats that gives you a frightful presence each time you cast a spell. Or take Iaijutsu Focus, though that has very little to do with casting.[/sblock]
FWIW I'm just giving advice, so I don't mind if people read my discussion with Insight and chime in. I've sblocked to avoid sidetracking the thread.