I had a chance to buy one of these back in about 2001 for about $9,000. Mounts and everything. Ex-SAS. The shipping would have cost more than the rig. I kick myself for not buying it... and have thought about replicating one off a Chenoweth dune buggy.
Love the ideas above German and others... And the idea of a cut down LMTV is awesome.
Here's another rig I always thought was amazing and would not be hard/expensive to build. Storage is the problem!
That would have been the terror of Route One!
Cheers,
Sirhr