I saw a video today of a guy that had both of his trailers sprayed by line-x and he said that they worked great. He said that they sprayed right up to the CC and the heat hadn't bothered it but you need to keep it about an inch away from the FB or it will chip off.
The bed liner stuff is awesome for a lot more than just truck beds. I Made a table out of plywood and steel then had it sprayed. Works absolutely great for a prep table when I’m out camping. A few things to mention is that it is not a smooth surface so grease/oil/dirt will accumulate in the crevices and be hard to clean and that the coating will melt if exposed to heat. I set a Dutch oven on the top to serve dinner and the “legs” melted into the surface.