Ones I'd like to see
Thog is tops for me, as you probably well know, followed by Wayne & Wanda, Mahna Mahna, Uncle Deadly (so cool-looking), Blue & Green Frackles, Nigel, Lips, and George. Might be nice to have Gorgon Heap (hehe) or Behemoth, one of the monsters that eats other characters, and make him (or them) hollow so they can actually fit other smaller figures inside of them. That's too much hoping there.
As to Mary Louise, I don't think this was the character's name (it was the name of another, ugly Muppet female initially voiced by Jim Henson). The character that Alex was referring to is the one with the long brown tresses and sort of almond-shaped pretty eyes. Very pretty-looking Muppet, usually in At the Dance. I'll list all the sketches I can think of featuring this character, and Alex you tell me if I've got the right character:
Joel Grey:
Wilkommen (sits with Dr. Teeth)
Ruth Buzzi:
At the Dance (dances with Boppity, three jokes)
Paul Williams:
At the Dance (dances with Animal)
Harvey Korman:
At the Dance (dances with balloon-headed man)
Peter Ustinov:
At the Dance (dances with Rowlf, gets punched by the punch bowl)
Sandy Duncan:
At the Dance (dances with Rowlf)
Avery Schreiber:
At the Dance (dances with Rowlf)
Vincent Price:
At the Dance (dances with vampire)
Twiggy:
At the Dance (dances with Sam the Eagle)
Ethel Merman:
There's No Business Like Show Business (one of the chorus girls)
Mummenschanz:
At the Dance (dances with Rowlf)
I know there must be more, but I can't recall specific At the Dance scenes right now.
As to her being a figure, won't happen. She doesn't even have a name, she's just Female Whatnot.
David "Gorgon Heap" Ebersole