bilbous, this is actually not far from something I had been planning for a different kind of roleplaying event for new characters only (the core part).
All characters would join a House (guild). They are all required to play certain types of characters with a specific goal. Points are awarded in an in character manner for actions, reactions, popularity, and sanity (staying IC). Winner takes all.
If a person can not stay in their semi-assigned character and follow the simple rules, well then, they are not the roleplayer they thought themselves to be.