Z- Thanks. I used the platform on a trip our NCRC group took to Blue Lakes in NorCal earlier this year. It is pretty comfortable, although I think I am going to get a much thicker sleeping pad, maybe even an AeroBed. I do have a roof rack that I throw the extra stuff on top if I deem it necessary. You can't see it, but the wood panels are joined using angled aluminum extrusions (1"x1"x1/8" thick) and screws with threaded inserts. Took a little time to cut and drill all the angle brackets, but I am working on a complete kit that includes the wood panels, angle brackets, threaded inserts, screws, slide rails, carpeting and drawer locks. I am still finalizing the designs of the wood panels so I can get a quote from a CNC router company. What I really like is the whole think bolts to the floor using the four factory mounting points so it does not move at all and yet can be removed in less than 10 minutes.
JH, The seats are under the extended platform. I designed the platform so I didn't have to take the seats out, but you still have to tilt and move your front seats all the way forward. I did take the rear seats out once for a trip, but I found that the extra 12" of headroom wasn't needed. Now with the platform I don't have to remove/replace the seats for extended trips, and actually have more flat surface for sleeping.
If anyone wants to build their own, I can provide basic plans. All parts were purchased at either HomeDebtpot or OSH. The only think you can't buy there are the drawer side panels that I had my company make out of aluminum so the slide rails would mount perfectly.
Chris