X2 on DocBrown - I did a LOT of research, and only came across two companies that had anything they would allow for RV use - Swagman, and 1UpUSA. And each only has a couple of versions. None of the majors (Thule, Hollywood, etc.) have racks for RV use. Every one specifically notes they are not to be used on trailers. As was noted, the exaggerated sway and bounce is just too much for most.
2012 Ford F-150 Eco, Max/Max
Jayco 26.5 RLS, Reese Sidewinder