The Jem movie did Jem dirty. How the hell do you screw up that concept?
Though I suppose Hannah Montana was basically a Jem imitation? I didn't catch much of that show but it seemed similar in principle.
I'd like to see them do boardgames, especially the ridiculous stuff like Fireball Island. The Milton Bradley Gamemaster series (Axis and Allies, Shogun, etc) and Avalon Hill would be goid subjects as well. Parker Bros would be much more mainstream though, and I'm not sure how sordid or sinister the story would actually be.