Out of all the recommendations so far in this thread it's got to be vbulletinskinz without a doubt, it's just whether or not your looking to spend that much.

On the other hand, I think a contest would still be a good addition aswell as hiring someone else. I'm pretty sure a majority of the designers here would have a go, I doubt you'd even have to offer a prize for it other than a link at the bottom. (only thing that'd cost would be to get it coded and thats like what? $175?). At least this way your getting the members more involved and the members who think all the designers are **** here would also be kept happy.