That's not a bad idea...maybe do a little Scooby Doo set...
I've thought about doing some other cartoon characters as icons in the past- the shading would be very easy.
For a while, I was even working on a Simpsons mod. D'oh!
Other cartoon mods I've started at one point or another:
Transformers (I know, y'already knew that one.)
Power Puff Girls (Who wouldn't want to fight Mojo Jojo?)
Pokemon/Pocket Monsters
G.I. Joe (the original cartoon series)
Smurfs (don't ask)
Super Friends