I just got the soundtrack to DJ Hero and I can totally envision couples mode simfiles for many of these songs.
I personally don't like the idea of DJ Hero (pretending to mix pre-mixed songs doesn't excite me although the music is great).
But listening to the songs I could imagine playing these songs in couples mode with each person playing steps to one of the two songs. The songs are all blends of 2 other songs switching back and forth and mixed together throughout. So the steps would be almost like two people playing two different songs at the same time. There could also be some interesting stuff for both to do during the mixing and scratching.
My problem is I have never created couples mode... Anyone wanna steal my idea and run with it?

