Although, to be fair, I'm sure my idea is somewhat derivative as well... I'm not sure of what, but I'm sure its been done before.
I've really always wanted to play a Somnambulancer in a Mage game. I figured it would be pretty hilarious to have a character whose focus for everything is being asleep, and therefore is rarely actually physically present to get things done.
"Yeah, Ok guys, I think I can help you break into that warehouse. I just gotta go home and take some ambien, call me in the morning, let me know how it went."