Window protector, And sides

Well Yes another truck question, I want to put sides on my truck but my dad wants to still be able to use the back window when we are empty. I see headache racks for about 200 and it just seems ridiculous because no ones even going to see it, I was curious if anyone has built a window protector or something like a screen bolted on to the sides, I was thinking of using U bolts on a 2x4 frame then put the sides on, And for that I just want to rip a 4x8 board and put them on 2 foot high and use security bolts to hold em onto 2x4s in the stake holes. So anyone know of a way to homebrew up a window protector for less than a hundred? and without using a piece of plywood? Oh and also for tools I have most woodworking tools some metal but no welder. so I wish I could just weld my own.

Mine are homemade from scrap iron...Square tubing and steel mesh with no vertical sides. The sides are just flat iron with holes drilled through them and matching holes in the top of the bed rail to bolt it on. Wouldn't be to tough to add in a trap door to have access to your sliding window