Well there was the 145 Express (has a hi-top over the cargo area), 245 Transfer (extended wheelbase wagon for more passengers), 245 hearse (2 doors, extended wheelbase, extended back), 245 ambulance (3 door, extended wheelbase, much taller in back), and for the stripped down, the simple 245 van (2 seats with a steel wall behind, and a flat cargo floor all the way back).
FWIW, I've thought of such too, seeing the occasional nice Volvo with a wrecked rear that could be cut out and something else put on it. Only thing - they handle bad enough as it is ... add more weight and move that center of gravity higher, and it'll get much worse. I should know - I've been using my homemade roofrack a lot recently(*). Despite wider tires, stiffer overload coils, and sedan turbo sway bars, my 245 handled worse than stock under load.
-- Kane
* - Saturday was plywood, sheetrock, and some 2x4x8'. Sunday was a pile of fence boards, some 4x4'8', a couple 2x4x12', a 4x10x8', and about 200lbs of marble tiles inside. Monday, I had a few 2x10x8', a 2x8x16', some more plywood, and cement inside.