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.