Just got back from Afghanistan and, after a weekend relaxing with the family, jumped into building a sleeping platform. Probably took a total of eight hours, some of which included putting together a saw and finding tools in the garage since I'd been gone.
Made a mistake in measuring the top because I didn't account for the side pockets or added width for the carpet being folded over the sides. Ended up trimming about a half-inch off all sides of the middle panels and hatches to fit.
Also added two cross beams at the center. One on the driver side is thirty inches from the tailgate; on the passenger side it's forty-eight inches.
Thanks to Hatch017, Pugga, Deeznutz and Wicked2007 for design ideas.
Getting the topper tomorrow, post more pics then.