Simple, yet not so simple suggestion, how about in game references to Vorbis streaming outside the game? Since LL obviously doesn't want music uploaded in the form of full songs (by way of the 10 second sound clips) and copyright stuff, deal with it all externally, just point to something like icecast2 streams, which happily use ogg vorbis, and allow the client to accept the streams?
IE: I put in an object with a llGiveStream() reference on a script touch, you touch it, it offers you a icecast2 stream location, you accept, stream starts, audio plays.