I've seen black, white, and a sort of beige color. Don't really know of anyone who carries the beige though. If you want different colors, I posted instructions in another
thread on how to change a white cart into whatever color you want.
http://www.e-cigarette-forum.com/forum/tips-tricks/123572-keeping-track.html
I found the method by accident and experimenting and have been making different color carts out of some white ones ever since.