I've got an idea too and thought I'd run it by you guys - it's called I'm Still Not There, and it's a biopic of Joaquin Phoenix told in episodes. Each episode has a different actor playing Phoenix - so far I have John C. Reilly, Crispin Glover, Tony Clifton, Natalie Portman (she's got the Joaquin mannerisms down pat!) and Jeff Bridges in a futuristic sequence imagining Joaquin in his 60s.