So I discovered a quick n' dirty alternative to diamond treadplate for fenders or a rock shield. I haven't used it, but I wonder if anyone has, and if so, what's the verdict. It's a peel n' stick vinyl gravel guard. Can be bought per linear foot or by the roll. It often seems to be used to protect the fenders or the lower front siding.
Source: http://www.tjtrailers.com/store/product11254.html