Has anyone ordered or used one of the package shelves for a 4-door JK on a 2-door model (without the rear seat)? I would like to know if these will fit behind the front seats and go to the tailgate. I would like to have 2-level storage for my long distance wheeling trips. I thought about using a small roof rack and welding mounts into the Jeep but I have noticed that several companies list a rear tray or shelf for use in 4-door models. Any thoughts would be greatly appreciated!