I can't think of many. There's a Bela Fleck piece called "UFO Tofu" where he tries to do some musical palindrones (the title of the piece is a palindrone). Anyone else?

I think the melodies in ELO's "Fire on HIgh" are supposed to be reversible. There's even some backwards speech in the beginning that tells the listener "The music is reversible... turn back, turn back" or something like that.