I don't know if it's been mentioned here, but archive.org will stream most of the shows that the Dead ever played. If you want to hear the evolution of songs from 1968 to 1995, it's all there.
Nick, as far as I know, Alphonso played a Modulus. I saw Jazz is Dead a few times as I used to hang with Jimmy Herring a bit. It was great to meet those guys. Al and Billy Cobham were really nice guys and Vassar Clements played one of the show as well. I have some nice soundboards on DAT somewhere in my basement. Their take on the material was pretty interesting, although a lot of the details got left behind, mostly things you'd notice if you'd played it yourself. I'd don't know if I'd call it jazz per se, but it was a nice idea. I would like to hear Jimmy play in a more straight ahead setting.
I have never seen Al play an Alembic, but anything's possible! At one of the shows, Jimmy had a prototype of the Paul Reed Smith hollow body guitar that sounded great.