Hi Andyman:
Many years ago... about 25 ,,, I was going throgh a pile of junk vehicles looking for parts and came across a AD bus. This vehicle was looong wheelbase... and had a row of perhaps 3 or 4 Roll Down windows on the sides next to a row of seats. As I recall there were extra doors too but not sure.
There was a metal plaque that said this vehicle had been modified (built- converted) in Spokane WA.
It was very well done as I recall, but at that time I was only interested in pickups and left it to be crushed. Hind sight is so cruel!!!
I would guess that there were many different companies the converted vehicles in the '40s and '50s for other uses.
Am interested to see other posts....
Ter