It's been awhile, but I went out for my kickoff trip this year, and it made me think of this thread. I never posted pics of the rear platform.
Well, here are some pictures. I made it from a single sheet of plywood, reinforced with some aluminum angle. Very light, and creates some very nice storage. I store a battery, 6 gallon fuel tank, preservers, throws, etc, and still have room for a second fuel tank, if desired. Very useful!