Thanks heavy. I guess I'm going for a balance of agility and ruggedness. I like edoubleaz ideal of using Lexan (Polycarbonate) sheets for fabrication. It would be lighter than metal and the stronger than any kind of styrene I could use. Plus, I can cut fairly easily, glue, sand and shape it. What would be a recommended thickness? I know that there are 1/8" sheets on ebay. It would be relatively easy to cut and when glued together would from a rigid box that can be further reinforced.