I used a flat sheet of aluminum with 1" square tubing riveted to the underside. I riveted 3/4" angle to the bed rails to support the cover and help it lie flush with the rails.
I am not sure if I will cover it with auto top vinyl, paint it, or sand it to give it a brushed look with shiny rivet heads.
No top or closed pics . . .
The tailgate will open by remote with a door solenoid and my remote. I also need to add some struts, but need to find the right ones first.