HI,
Have to think a bit ... but some come to mind, right away:
Seventh Wave - toured with 5 or 6 keyboard players. Their two albums, if you have never heard them, are magnificent. Not sure this could be done otherwise. Nowadays, you probably can do this with one keyboard! One of the members here saw this show ... sorry, can't remember which.
Caravan - Was missing Pye Hastings for a couple of shows due to illness ... so the Violin/Flute player assumed all the leads. The version of "For Richard" (long 15 minute piece) is actually better than the original ... and without vocals.
Tangerine Dream - One of the nicest things in the Phaedra Anniversary Concert, was ... all main members (Edgar, son Jerome and another) all played guitar ... and it sounded magnificent. I did prefer, 35 years ago, when Edgar played the guitar in "Purple Haze" ... but he mostly sticks to keyboards now. Easier on the buns, I think, if not the fact that the amount of work and coordination that these folks do, is insane ... and not for everyone.
Hawkwind - Doesn't matter the line up ... Silver Machine and Master of the Universe still sounds great!
Roger Waters - The latest/last version of "The Wall" was actually better than the original, and cleaner in every aspect. The visuals were better, but the "quadraphonic" sound was missing and that was one of the big things that made PF really cool in thsoe days ... sounds going all over the place and around you! Digital, however, was way cleaner than the original, that was hiss'y as hell!
Gong - Without a keyboard player, this band is fine, but never half as good as the original. Also of the 3 times I saw them, it went like this ... with Pip, it was jazz'er. With Chris is was more disco'd in the drumming ... simpler that is. With Pierre, it had a massive rock edge that made it stronger for me! With the leyboard player on occasion ... it just wasn't there, when the original was not there. But it was still good, just different. And Gilly never failed to do her part and do it well. Daevid is the same way ... always ready to party on the stage. He's a ham, incognito!
The Rocket Scientists (and with Lana Lane) - Various disks show a couple of different guitarists, but in the end, the live shows are always clean and strong and well done. With a magnificent bass player on the Sticks, a keyboard player as good if not better than Keith (and he has stated so!), these guys put on a massive show at a Progressive Rock Festival, and were not appreciated ... because they were "too metal" at times. But they were one of the most professional and clean bands I have ever seen ... and dedication like that deserves recognition! I would like to get Bapu a Stick for Christmas when I get to be a screwed up millionaire that can spend the money ... just to see his face ... it will be worth it!
More as I think of it