Design me a pickup box.

[rayfinseats]

Suggestions?

83 chevy k10.

Requirements: Must be cheap, light weight, highly rust resistant, 4'x8' or 5'x8'.
Need not carry really heavy loads but will be used to carry light loads. No flat beds. Must have sides at least 2 feet high.

I was thinking about making it out of angle iron (rhino-lined) with a plastic slat floor (composit decking) or a tube frame box.