Went out and did some measurements of my Gen 1 roof. Really thought it would be considerably longer than the Sami posted at the beginning of the thread. It is a little, but not to much. I figure I can get a 68 x 48 mattress / sleeping area. Width is OK. Length is probably OK. I'm 5'8" (and shrinking it seams) and my wife is 5'4". Won't be as spacious as the RTT. Found 2 fabricators local capable of doing the aluminum work, bending and welding. Will see what they come back with cost wise next week.
Well out at 6'5" I don't think I'll fit. I built a sleeping platform and with the seats all the way forward its just under 79" and 54" so that should be OK