There's really no limit to who wants to MST right now. Fact is, we were trying to encourage shadowMSTing from people (such as Zetaszol, for instance, who seemed to have disappeared after going all dramatic. Where are you? ^^;;). As long as the jokes are okay and done in good taste (no excessive author-bashing, etc.). Oh, and read the IFR style guide... we can always just edit out something we don't like. ^_^
Of course, you'll have to use the avatars already in the theater. No seats available as of now.
Handy list of Avatars:
Jonatan
MMK
NeoVid
Ranma X
Rebecca
S.D. Ryukage
Tango
Vidstudent