Your business plan looks solid. Wonder if purchase, maybe damage repairs are comparable, composite vs. aluminum. Curious about weight differences, probably most important to overlanders.
While I can't 100% comment on the purchase stand point of the composite bodies (seeing as how we get different rates than what other customers might), I will say that I have not seen any drastic cost inflation especially since any increase was quickly negated by being able to downgrade the truck (going from a 3500 series to a 2500 series).
The maintenance is hands down much cheaper on the composite units. They stand the test of time much easier. Since they are not affected by things such as rust (other than maybe on the hinges and handles) they, in my opinion, tend to last MUCH longer. Should parts be needed, the company we use has been using the same moulds for numerous years. Parts (things such as doors which are our most common repair from operators knocking them off) are usually a 3-5 business day shipping deal, and in matter of minutes a new door is installed. As a testimonial, we have a 33k Service Truck with a composite body that has been in use for 14 years. Other than some surface dirt and grime, the body looks brand new. When this unit is retired, I will be spending the small amount to have it refurbished and remounted on the new cab and chassis. There is no need for hammering out of dents and dings, as witha composite body doesn't get those.
Weight: The composite bodies tend to run around 40%-50% lighter than their steel counterparts from the information I have seen. This is one of the biggest reasons we went with them was the purchase price of the cab and chassis by downgrading the vehicle and also the fuel savings.
Hope this info helps.
Edit:
I just remembered that my vendor is coming out tomorrow to give me some ideas on a new project truck we are building. I will be sure to snap a few pictures of the demo service truck they are bringing out and post them up.
