The waterproof LED lights that I had ordered from Deal Extreme months ago finally arrived. I already had one of these brought a long time back for playing around with, but needed another two for the skateboard. The plan is to mount two facing the front, and cover the remaining one in a red filter of some sort and make it rear-facing. They run directly of 12V, and are easily mounted.
More pictures of the design can be found on the Electric Skateboard Photo Gallery Page.