My whole literary career seems to be built on genre-mixing. For almost 20 years I've been mixing erotica with science fiction/fantasy, which used to be very odd and is now pretty commonplace. Now I'm writing paranormal romances, which are a combination of fantasy with romance. I've also mixed literary fiction, sports fiction, and fantasy...
I don't do it consciously -- it's not like I'm *trying* to make a pitch like they are in the opening scene of The Player, ("it's 'Out of Africa' meets 'Pretty Woman'..."
http://www.youtube.com/watch?v=0epB5Z6ijpk) but I just can't seem to help using one genre to pry open the cliches of another.