A Vixen, eh? How about the other rare super slick RV, the Navette?
Weird RVs: Navette motorhome is a sleek rig
Look up the one-off Tony the Tiger Navette, commissioned as the carriage and support vehicle for Kellogs Frosted Flakes hot air balloon. Someone in Weiser, Idaho bought and restored it and has or had it for sale recently.
Last I checked, the guy who designed and built the Navettes got cancer, survived the treatment and has since been attempting to sell all the tooling, a bunch of parts and one complete vehicle. It would be a kickass RV to see in production again, though it would have to rejiggered for a new chassis.