One welder I know purchased an old ambulance. Not that old, it had a nice cube body and low mileage. He used it as the basis to build a portable welding shop on wheels. It has plenty of general lighting around it so he can work on equipment in the evening and nights. He has a telescopic pole to raise a set of quartz lights for putting good lighting on whatever he's working on. The welder, a trailblazer CC/CV with GTAW high frequency is the mainstay. It is capable of providing current for welding as well as an AC power source for nearly any piece of machinery he needs. The welder is on a bed that pulls out from inside the cabin so there are no fumes, oil drips, etc. inside the cabin. The are cabinets on the outside of the cube for things like welding leads, torch hoses, come-alongs, chain falls, etc. His electrical powered tools are stored inside protected from the elements. He can stand up inside the cabin and he has a drill press and band saw that are also protected from the elements. There is a small door on either side of the cabin that allows long pieces of angle, etc, to pass through the cabin so it can be cut on the band saw.
The truck has a heavy duty alternator, so he has an inverter connected to that and the dual batteries for intermittent power when he doesn't want to fire up the welder.
He has a work bench that folds down from the rear of the cabin and on it he has a heavy duty vice. The bench is powered with a hydraulic ram, so there is no back breaking effort required on his part to set it up for use.
I only saw the truck once, but I was impressed with his ingenuity and his set up.
Best regards – Al