Unicell is a company that makes fiberglass bodies for commercial vehicles. They built the shell of the camper that Don and Kim Greene are using in their travels through South America, and now New Zealand (See www.questconnect.org).
The Unicell web site has details of a truck body for Ford and Chevy vans called the Aerocell SRW that might make a good travel vehicle if you do not plan any rock-hopping off-road excursions.
The streamlined body is of composite construction. The body is molded in one piece, including a skylight to brighten the interior.
The rear door has two designs. In the first, the rear panel is hinged at the top, and the entire back of the vehicle opens upward. The second design is a small double door like you'd find on a conventional van.
Windows are optional, and can be placed anywhere you want in the vehicle.
the Aerocell body is strong enough to mount ladder racks on the roof for extra gear, kayaks, windsurfers, and so on.
The Aerocell/SRW is designed to fit on a one ton, short wheelbase (about 135"), single rear wheel van. Dimensions inside the van body are:
--129" interior length at the floor
--75" or more width anywhere above the wheelwells
(enough to put a reasonably long bed sideways in the vehicle)
--74" or more interior height throughout
Here's the big reason to consider this van body: 430 cu ft of interior space, compared with 250 cu ft in a standard wheelbase Econoline. That's way more space than you'll find in a Sportsmobile.
More information here:
This year, both Ford and Chevy offer a diesel engine option in the one ton van, but neither offers all wheel drive. So you'd have to hire a company like Quigley (www.quigley4x4.com/) or Advanced Four Wheel Drive Systems of Salt Lake City (http://www.afwd.com/) to do the conversion (about $10,000). Or stick with a stock limited slip diff.
Unicell offers a range of options, including windows, side doors, and interior fittings.
Vans have great approach angles, and OK break-over angle, considering the long wheelbase. The Aerocell is not designed with departure angle in mind.
Since Unicell is willing to make custom modifications, maybe they could trim the sides at the back so they go upwards instead of parallel to the road.
The Aerocell/SRW van body is bulbous. It has kind of a "Conestoga Wagon" appearance that is starting to grow on me. I saw a van like this recently, and it looks smaller in person than in the photos.