I've been contemplating buying a Vixen with the 21foot long 21td (turbo Diesel) getting 30mpg. the drag coefficient for the Vixen at .29 isn't far from Teslas .24 for model X. Not bad for something 8 inches wider than an Econoline van and 21 feet long that just barely fits in the average american garage.
So....
I spoke with one of the best Vixen techs. turns out the drawings for the original body panels are still around.
Personally I have a lot of ideas for a compact RV. Especially ways to instantly reconfigure the RV so that items that are used sporadically can hide away leaving more livable space.
The entire floor of the coach could be batteries. A Model S 85kwh battery weighs 1200lbs. There are 14 modules in a battery pack. Figure on about 85lbs per module. The Vixen tips the scales at about 5000lbs. assuming you would want a 400 mile range on a single charge and perhaps enough charge to get through a night ( B. Nyland of Finland used up about 40km of range sleeping in his model S in winter.) Assuming that the Model S is mostly uninsulated glass without huge concern for R factor -whereas the Vixen is 2 inches thick of foam coated by fiberglass (Nearly a picnic cooler) and a second airplane quality interior plastic layer ...the heating requirements for the cabin might be close.
So I would guess 22 modules would come in at about 1700 lbs assuming more mass might need slightly heavier gauge metal for containment in the event of a crash.
Having more batteries and being to use adjacent cells that are not being drained as heat sinks might add some efficiency to the equation by having the batteries run cooler and more efficiently- and correspondingly being able to run batteries in larger clumps when cold might also gain some usable range.
Now it starts to get fun.
Add an air2water maker. Remember those dripping air conditioners?
Atmospheric Water Generator, Drinking Water Machine, Air2Water
Well you may as well feed this water from an AC which you can run backwards as a heat pump..and heh heh , a humidifier if needed.
That takes care of some of your water tank needs and allows for indefinite boondocking (camping without a hook up)
Add 2 flaps in the roof line on either top edge length wise - that can deploy dual flexible solar generating canopies that can be tilted on sliders to change the angle to capture the sun more efficiently (and add wind sensors so they retract in gusts to protect themselves) .
On top of the roof you can integrate a solar hot water heater just below the flexible solar sheeting- or perhaps a dedicated area. Using counter current flow you could run a large portion under flexible solar and then a smaller section through the final solar heating chamber. Temperature and altitude sensors monitor to avoid boiling points to keep airlock from happening. This heated water goes to tanks which are well insulated protected against freezing- and could be heated if needed. That water can be pumped inside the walls of the bedroom and living areas for sleeping for warmth to reduce battery heating needs.
The toilet is a composting type to eliminate the need to dump a black water tank and greatly extend your boondocking. Some grey water could be used for hydroponics.
So you would be electrically independent , water independent. And with Autopilot you really could go just about anywhere comfortably. Ideally the coach could be extended to the rear on tracks when parked and could widen- but instead of using a slide out "pocket drawer" The RV would be specifically designed to widen on rails and use inflatable aircraft accordion seals to lock out noise and add rigidity along with a slide panel to fill the roof void (not unlike a giant sunroof sliding in place like a leaf in a dining table.
Reach for a couch on the RV- slide it forward to reveal a shower pan and a extending tambor wrap to create an instant shower stall of considerable size-better than current cramped ones. The shower completely disappears when not in use.
Pivot two couches into a facing dinette exposing a wall space from which drops down a hidden sink, and kitchen area. A sliding panel reveals a super slim Induction cook top. Which can even be fooled up and removed. These would work on higher voltage. induction cooktops do not get hot.
Roll Up : Foldable Induction Cooktop by Goran Bjelajac | Tuvie
Sometimes people want to sleep while others are still reading or watching television with headphones. This presents a problem as some couches need to be turned into beds. but can't be both at the same time..... or can they?
Watch from 5:20- 5:38 note there is some storage still available under the bed. Again a tabor on a rack can slide out from the wall to give the sleeper privacy. Locks could be added to lock the bed in place. This is an interesting solution as compared to beds that drop down from the ceiling - That have little space to use underneath. Or from Class C style campers that are too tall to fit into an average garage.
Having this camper expand in width could allow it to fit in a double garage and create additional sleeping for extra guests within your own house.
I'd also fit a flat section that could unfold on the outside or another tabor to create an outdoor shower. With the recessed retracting tambor walls you could reconfigure the space on the fly from an open living room- to an office with a rear bedroom.
I'd use ultra quiet computer fans for ventilation.
For the main rear bed I might consider using a "Zoom-room bed" style mechanism as an option.
The composting toilet could store below and rise up out of the floor to meet with a sound roof privacy fold off the side wall. Just press a button to have it appear and set itself up flat fold out Plumbing would be inset into the wall as well as a drop sink. The toilet and bath could be separated or joined depending on how you set the panel preference.
And of course the Tesla RV would have normal creature comports - a nice flat screen, perhaps an internal reflected projector that could activate a lens on the Inside and/or outside wall for making your Tesla RV into a "Driving Movie", ahem "drive-in movie". There would be outside speakers of unusually high quality and a way to easily get the to extra induction plates for easy outdoor cooking- you wouldn't want cooking oil coating your RV? The inside burners should be more for reheating anyway. there should be a high volume low db jennair style exhaust for all RVs because there it doesn't take much to get the small interior space smokey.
And I would figure out a way to make it vacuum itself since you would get an endless parade of people wanting a tour.