Pugsley, the 1994 Thomas Vista Shortie
I pulled the trigger (for a second time) and got what I really wanted. It's a 1994 Thomas Vista Shortie (International 3600) with a 7.3 IDI. It was never used as a school bus and just as a people hauler for a mountain resort and kayak tour company. It has the type of rust one would expect spending its life in the Northeastern US, but only 73K miles! The price was right, too.
Someone purchased it from the original owner, painted it, and began ripping out the seats and panels before it became too much work for her and I found it. I have pulled out the alternate fuel system (WVO), and am working on patching the holes in the floor before laying the subfloor.
Interior usable dimensions are about 88"w x 160"l, with plenty of headroom. My ideas for the floorplan are below: