So, being a metalworker, I did a bit of research, and I decided to go with 1/8 inch flat steel plate, "hammered" (literally) for added hardness/strength, finished with the paint that was mentioned in the earlier reply. I'm still refining the design a bit in cardboard, and 2 front plates are officially in the works also; a stock size and a larger one covering the diff and such. I'll keep everyone posted and try to get this out reasonably quick.