Nice!! always wanted a project like that. Had a few in mind ranging from a 1941 Willys Jeep right up to a Challenger 1 Main Battle Tank 
There's a guy somewhere in Britain that at least used to drive a tank to work every day. I remember it was painted bright yellow.
I did know someone who had an ex british army ferret. 4 wheeled tank, street legal. He could drive it on the road even in the US.
As far as the ambulance goes, I think I'm going to rip out the interior and redo it. I'd contemplated leaving it as it is and adapting it, but it'll be more efficient to redo the layout. I already got ahold of a 3,000 watt inverter (27 amps at 110 with a startup load of double that, a standard outlet in a house is capable of 15 amps for reference).
The other side of the truck has exterior storage bins, I'd like to get ahold of a small diesel generator for one of them, but as it is it has a very oversized alternator and that combined with the inverter will let me run just about anything I could put in it. Current fuel capacity is in the neighborhood of 50 gallons, although I'd like to add another 20 or 30 gallons to that figure.
I also have some air tanks off a semi truck I'm going to mount underneath along the frame to provide compressed air for air tools (along with a compressor of some sort somewhere on the truck). It should work out to a fairly self sufficient remote camping rig.
