Cool idea! for the SWB, what if you had an extension? say the hinge is at the windshield. at the rear, after the top is lifted, fold out a 12" panel on a piano hinge. have the tent material draw taught from it being opened. can use some simple turnbuckles to suck it down and tighten the fabric. will give you the slight added space you desire, in a simple format. when done, fold the panel back into the truck and lower the top. should be doable.