Wilton's Roadtrek Windsurfing Rack. Actually it's more than just a windsurfing rack on the back of his Roadtrek. He also carries two bikes on it. Here's the link:
Roadtrek Windsurfing Rack
(and Bike rack
Wilton used 40 feet of one inch square tubing and a 2 inch by 1/4 inch support plate. He did all the cutting and welding for it.