Here's a quick doodle of the elaborate ending I'm dreaming up. The sides lean in, the front angles forward, enabling it to slide a couple of inches forward from where it currently sits (note rear overhang), the top gets cut out and braced with a removable crossmember across the rear and a front-hinged fiberglass tonneau (which I already have from a previous Ranger iteration) attaches to the top. I either need to narrow my tonneau or swap it for a narrower one from a step-side Ranger if that width works as-is (obviously much less work. Front-hinged cargo box will mount on roof rack tracks and hinge forward similar to a 1968-1973 Westfalia camper pop top, using the same seal for the edges.
The tonneau would serve two purposes:
1) can be opened or removed to accommodate tall items.
2) A three sided tent (think VW Westfalia pop top) snaps in for an airy camping setup.