Wow !!!
Lot of things to digest..
The 102 width issue is a directly tied to the frame width of the truck typically 34"....Engineers have figured that hauling cargo using an 85" height unit will become unstable over an 8' box...
I just thought of something...go to the Supreme body website they have a unit on a E-350 or E-450 chassis with a rear jump set configuration...it take up about 2 feet and then leaves 12' for cargo..
This may be a way to achieve what you are wanting to do
Cab to axle lengths are also critical most cutaway units are 80"CA or 100"CA...they are setup when you specify the body length...mostly for balancing the cargo load.....
I use a computer modeling program that GM developed for specing my ISUZU NPR's...it will calculate the load placement when you input info like the body length, cargo, liftgates, etc.... you get the picture.....I have always found that the recommended cargo placement is almost never sitting over the axles...but ahead of them for optimum load balancing...
Bottom line is that all this stuff affect the running of the truck (i.e. fuel usage)
I have a client that runs Unicell 14' box vans with E-450 chassis (gas V-10). They run from Chicago to Miami and across and north to PA.....about 50,000/year/truck...They use the trucks for rolling shops...about 4000 in constant weight....Gas mileage on these units is about 6-8 mpg....
They have 1 Powerstroke 7.3 and it gets about 9 tops....
Well anyway....I support your idea...I'm just not convinced that a cutaway truck is the answer...
Cheers!!!
Frank in Pa.
"The Beast in the East"