I bought one of the 5 Layer "Waterproof" covers offered by USCARCOVERPRO on ebay awhile back. Not a bad cover for the money, but at this point I couldn't endorse the waterproof aspect as being all that accurate. Maybe one of the higher multilayer offerings would prove being capable of that?
It's also not as much of a custom fit as the Wolf cover that came with the VX when I bought it, but that one wasn't as thick and over time simply started developing rips that it wasn't worth patching.
Unfortunately, I don't have one of the "24'x24' attached" type covers to utilize for the VX at the moment, but I would agree, that's the way to go, for any vehicle.