More I think about it, I DO like Jake's idea of having that panel be entirely removeable, for those times when you need to move something like a refrigerator perhaps. You'd just need to beef up the perimeter a bit better - a square tube roll-bar could work well, and provide a nice flat surface for the back panel to bolt to.
That's exactly why you'd want that area open. The standard for cargo capacity is a 4x8 sheet of ply. Of course, there is only 3' of space between the wells on a Scorpio, but you can fit a 4' sheet at an angle.
Not that I would do it, but if I did, this is how (now why does that sound familiar?).
- Remove the hatch completely
- Convert the rear of the hatch into a downward folding tailgate, so that when open it is level with the floor of the cargo area. This will likely require some modification to the bumper are, creating a stepdown for the tailgate.
- Convert the split rear seat into a one piece unit with weather seals.
- Add a small upper rear glass
- one of the challenges will be what to do with the C-pillar glass. Whether to leave it, remove it, open that area up, etc.