I was thinking last night that Transformers would be a good setting for a role-playing game. Vehicles which transform into humanoids provides the wealth of choices gaming geeks love when creating characters. The TV series featured good/evil groups and some world backstory, but transformers could just as easily be set in a heroic setting of a GM's choice.
I suspect the license-holders for Transformers don't think there's enough audience cross-over for current Transformers fans and current role-players to make such a product successful. There was at least a seven-year gap between the time I was into Transformers and the time I was into AD&D. But I see at least one person has created Transformers RPG rules
based on another system. They could just as easily fit into GURPS, d20, or many free-form systems. You could even run a game where just one character can switch between a vehicle and a big metal guy; the rest of the characters could human or whatever else. Maybe I'll try it out in the next Over the Edge game I play.