I recently did a similar rack. I wanted a rack to haul ladders, mount my plow light, and antenna's so I didn't have to mount or drill holes in the truck roof. Store bought similar units were $450. and up so I decided to build my own. I bought 2 - 20' lengths of 1 1/2" x 2 1/2" heavy gage tubing for about $150. and built the attached to fit into the stake pockets. I should have took pics as I built it but wasn't thinking of posting it here. Mine took 2 evenings, and part of Sat. & Sun. to prime and paint. Total of about 12 hours. By the way, nice touch on the horseshoes.
George