Welcome Mike- Took some time off from the HAMB to come and visit us?
I've seen a couple of the cabs you are talking about. If I remember right they were built by a coachbuilder and not directly by GM and were used for military use, as firetrucks etc.. I've seen a few of these custom built for COE rod haulers using a couple of cabs and a bunch of doors. I'm not much of an Advance Design truck expert, maybe someone else can jump in and help here. Please take pics when you look at the truck!
