King Kong. I was really surprised to see that there has never been an official release of a King Kong pinball machine (I guess it was Godzilla that made me search). I know they came pretty close (with some prototypes floating out there), but for some reason I find that this is a franchise that really should have an official machine. King Kong would be excellent, with e.g. "fight other monsters", "break the chains", "attack the city", "fight the planes", "catch the girl" modes etc.
What do you think? Any other themes/franchises that really should have a pinball machine?