[aerohead]

Home Depot carries something called R-MAX,polyisocyanurate rigid insulation board,in 4 by 8 sheets,in thicknesses up to 3/4-inch.The board is like polyurethane,and is compatible with polyester resin,available in the paint department at Home Depot.

You can drape the bed of the truck with 1-mil poly painters dropcloth,and mockup the bedcover directly on the truck,cutting the foam with a utility knife,join the sections with masking tape,while using temporary supports underneath,then do wet layups until you've built-up enough glass to remove,and flip the unit for glassing the underside.

West System's epoxy is best,but Bondo's polyester will do .This is how I created my bedcover.Just don't let goats climb up on top of it!

Whatever you do,give yourself some vision to the rear and to the passenger side for safe backing,when leaving a parallel parking spot.With respect to the tailgate mounted rear spoiler,it is there to remind owners to keep the tailgate up for better economy.It is virtually useless aerodynamically and is more CRAFTSMAN-SERIES NASCAR hey-look-at me-I'm-a -high-performance-wannabe.

Final note,if you can build some compound curvature into your shell it will be even stronger,as it will become a geodesic structure with strength approaching that of an eggshell.Also better aerodynamically.Nature hates straight lines and right angles!