I'm interested in this too, as we have the same dilemma. What "theme" would you think for both genders in the same room? Currently ours is a brighter sky blue, so I think that's neutral, but everything accented is cars, as it was ds's room first.
Sorry for the ever so slight hijack, but I have been pondering new bedding for bdays that would compliment each other while still showing their interests.
Sorry if I haven't gotten back with anyone via PM. Still learning the iPhone app and not very "techy".