Here is what the current owner stated in an email:
"You can install all the 4wd components under another van and not use the frame from this van at all. Just swing the already engineered and fabricated suspension and driveline components into another van. Just swap everything in as assemblies. i.e rear axle with springs attached, front axle with steering and springs attached and then hang trans and transfer case on the back of the motor. install driveshafts and cut a hole in the floor for the transfer case handle. It would be straight forward and really not very demanding."

He makes it sound easy, but some shops make it sound like a nightmare. The suspension customization should already be done. The 4x4 donor van has a junked title and can't be title (at least no easily/legally) in VA due to this:

http://www.dmv.virginia.gov/webdoc/c...ohib_allow.asp

I'd love to "just swap the body", but I'm sure that is no easier or cheaper than swapping the 4x4 components. Plus I'm not sure of the engine condition.