Some ideas:
1) self portrait 3d cartoon version
2) pinky & the brain archetype characters
3) elemental creature/character
1 and 3 have both been done already. How about someone filming something and then everyone is given the same footage and then we have free reign. People can then be judged on idea, execution, comping etc. So adding CG elements to real footage. Would be a good test of people's photoreal abilities (Although the stuff wouldnt have to be photoreal.)
Or even a matrix themed competition seeing as it's out next month?
Alan
Technical Director - Framestore
Currently working on: Your Highness
IMDB