Rain

There is a HUGE precedent for this btw.
One of the biggest is that there was/were/are a couple of bootlegs of the famous concert at the Roxy, from which the LP/CD was made, and that more than half the concert, which supposedly is just as good if not better, is still not released, and the fans on the Zappa board are merciless on this account.
Apparently a video is also available and it won't be released because the Zappas do not own it, the folks that owned the Roxy at the time do, and they want to make the money off it, not share it, appears to be the story, and I'm not sure that the Zappa Trust is big enough, or rich enough to be able to buy this off that person.
To my knowledge, the only other boots that would be interesting to listen to of Frank's concerts, would always be his warmups ... period!!!! It's where some of his instrumentals came from.