http://www.audio-dvd-creator.com/index.htm
I've been playing with this for the last few days. It creates 5.1 mixes on DVD-Audio discs with some fair success. You can put about 8-9 hours of audio on a DVD.
To point out: right now, we are taking local college bands and creating a "sampler" DVD discs with all of their music + notes, etc.
(Note: if this belongs in HTPC that's fine, I just couldn't figure out where this would go)