I've seen what I think your describing done on newer Pathys and Xterras, the ones I saw they just used the wire closet shelving and flipped it over so the part that would hang down in the closet, was turned toward the ceiling in the truck and kept the items from falling toward the front, it was accesable with the hatch open, and with the hatch closed it kept stuff from falling out the back. In the ones I saw done like that, they used clips already in the ceiling on their trucks to attach them though. On ours you might get away with using the mounting hardware they make for mounting them in a closet and just bolt it to the inner body structure.