Hey Gary,
I just googled " RV 5th point mount" and a zillion images showed up, mostly aircraft related,...... and one fat naked guy in a motorhome...( do NOT click on that one!)
also check out the RV white pages, or just put a shout out on here, and you'll probably find a few RV's under construction in the lower mainland or the island (apparently lots of rich retired guys go there to build in peace!)
by the way, I don't have one, and hit my head on the canopy pretty often, so it's a good idea even if you don't plan on going upside down much!