I have a used deck removed from an enclosed trailer, aluminum frame, with pressure coated plywood decking, that had outdoor carpet at some point.
Could be added above a horse trailer for hay and other utilities if thats your passion,
This is also light enough it could be added above the gooseneck of a flat trailer for extra capacity for light weight items, if you haul hot shot trailer loads.
I was going to attach this to my 24 foot enclosed trailer to watch dirt stock car races from the pits, but changing trailers and not going forward with this.