> Why not buy a bus, fit a diesel and strip the interior out?

I'm actually considering it, if I ever have the free time and the space to
do it. The backlog of tasks on my current "fun" Vanagon is a long enough
list already, though.

Vans with
> no side or rear windows are plain dangerous (no visibility in parking
> & traffic), so a normal stripped van would be far better.

Dangerous? Nah! Not for an attentive driver with good mirrors. I've been
driving large windowless work vans for fifteen years and the one and only
thing I've hit was a light scrape along the passenger door from a 3 foot
high concrete filled metal post (something neither mirrors nor windows
would've helped). Now, certainly the stock Vanagon mirrors are less than
ideal for a windowless van, but the simple addition of a 4-inch convex
mirror on each side would fix that.

To save damage to the sides & floor, fit hardboard or thin ply side
> panels and make a wooden floor to spread loads. Beware, added
> flooring traps moisture... rust.

I'm thinking aluminum tread plate. I have wood with a rubber mat overlay in
my Dodge van and it just hasn't lasted. The mat gets grungy and the wood
underneath soaks up any liquid it comes in contact with. Not much problem
with rust from trapped moisture here in sunny Los Angeles, but I've been
enduring the sulfurous smell from a spill of thread cutting oil five YEARS
ago. I don't think I'll use a plywood floor again.

Ideally I'd like to replace the two aft side windows and the drivers side
mid window with either sheet metal, or even better, lockable doors hinged at
the top. The windows would be blocked by interior metal cabinets anyway.
Openable doors would make for handy access to the inevitable
otherwise-wasted space behind the cabinets.