I've done some outlines with some of these folks already- Billy Joel, Sammy Davis Jr., David Ogden Stiers, with several more in the pike- Alan Alda, Rodney Dangerfield, Gene Wilder, and John Ritter. I agree that Suzanne Somers would've been a good choice, and of course Gary Burghoff, Weird Al Yankovic (he didn't come to prominance until post-TMS, I think), Bill Cosby and Bob Newhart.
Some additions:
-Mel Brooks (TravellingMatt wrote an outline, Philip Kippel and I are working on another one)
-Sid Caesar (Princeton and I are working on this one)
-Henny Youngman
-Buddy Hackett (if I ever finish this one)
-Mickey Rooney
-Walter Matthau
-Jack Albertson (Grandpa Joe from the original "Willy Wonka", Oscar and Tony-winner as the dominating father in "The Subject was Roses")
-Larry Linville (I think it'd be interesting to see him being himself and not Major Frank Burns; in real life Linville was considered a great guy by those who knew him)
-Carole King (TravellingMatt wrote an outline featuring her)
-Rod Stewart (TravellingMatt wrote him into an outline as well)
-Mick Jagger (I'm taking this one)
-Dan Fogelberg (I grew up on this guy- I'll do an outline with him eventually)
-Gordon Lightfoot (got an outline started but it's a long way from completion)
-Cat Stevens (started an outline, a long way from finishing it)
-Jim Croce (if only he hadn't died so suddenly; I'm just starting to develop ideas for this outline)
-Spike Jones (again, died years before TMS)
-Cass Elliott (died in '74; working on this outline)
-Jack Benny (died in '74- Princeton did a nice outline guest starring him)
-Art Carney (he worked with them twice; if he had done TMS, he would've been their only guest star to win the Best Actor Oscar)
Cher and Robin Williams were supposedly booked on the show- in one of the Season Four editions of the Muppet Show magazine they were actually listed as upcoming guest stars, along with Senor Wences- but then they ended up not appearing, and Senor Wences ended up appearing the following season. I have also heard it said that Cher was booked (or re-booked, I guess) on the show in late Season Five, but once again dropped out and was replaced by Debbie Harry.
I think most of you know who I would've liked to see on TMS judging by my outlines. I just came up with another idea only yesterday, which I hope to work on during my vacation this week (I'm in Cincinnati visiting my grandparents). For now I'm going to keep it a secret, suffice it to say it's another Halloween episode, and a celeb who died years before TMS began.
David "Gorgon Heap" Ebersole