Actually had a close look at our van this afternoon (hooking it up to go down to the Inlaws (Narrandera) for a few days) and the front of the van actually has a spray on poly type coating on it for the bottom foot or so. I guess to minimise stone chips, so I don't see why a decent layer along the sides wouldn't work, the checker plate doesn't feel extra thick or strong so I think a good liner spray would be just as good.
It will be interesting to hear the price. Also the weight would be interesting too, just to see how it compares to a sheet of thin checkerpkate.