I looked for a RV Bra also, there was a post last year and I think the consensus was they caused more damage than they helped.
There was couple suggestions to have one made by a marine or auto upholsterer but I couldn't find a manufacturer that produced them. I went with a full cover I got from Amazon and have been happy with it. It is kind of a pain to put on but My son comes over and does the high hard work, Thank You Doug.
I'm going to watch your thread and hope you find something, let us know what you find.