[flashmedic]

another avenue to investigate...a friend of mine considered buying a used ambulance or heavy rescue truck. Some fire departments replace these very frequently and they are far from used up by the time they are retired...and they resell cheap! Cabinets, inverter & air conditioning/heat are already in place, as well as the scene lights for outdoor/night work (most states require you to remove the flashers). Most also have a plug in (though I'm not sure how they are wired, exactly).

just a thought...let us know what you get, and some pics after it is finished