Wouldn't it be just as easy to put on a CD?
Well, yeah
BUT: I was thinking maybe in the authoring, maybe Zion or MeBe could either a) make it so you can jump to the scenes those tracks are on specifically, kind of like how some commentaries are only for certain scenes on some tracks. I think there's some captures of the Def LD's that do that for the Def commentaries, since they're so sparse, or b) do it like the Superman DVD, where there's simply a menu page that allows you to hear select deleted cues accompanied by still images. If there's an image gallery, maybe you can select what track will play underneath them, or just select which cue you want to hear and the DVD will essentially BE the CD.
Obviously, Gerhardt's concert arrangements would play along with the scene pretty roughly, not screen specific, but it'd be a decent special feature to listen along to the alternate recordings.
but you do have a good point--ideally, these would all be dual layered DVD's. Image quality will only take up so much room when being captured from a LD source, so you could max out the audio tracks and not hurt the image pretty easy. Plus, you get into the whole "internet stealing" thing, because if you don't stick them on an isolated score track that attempts to play along with the movie, you're essentially getting a free copy of a CD that's still available for purchase. With these isolated scores, it's at least re-edited to play EXACTLY with the movie, deleted cues and all, so it's an experience you CAN'T get on a CD. But in this case, it gets iffy, because this is essentially just spreading out an existing CD on a DVD, no changes or edits at all.