The first year for the NC3V chassis Airstream and others were building on the 2500 chassis. Airstream actually built on the extended body 24 ft. Sprinter with the 2500. If you remember, they and others took a year off building Sprinter Bs I suspect in regrouping and maybe unpublished failures, though I traveled the Alaskan Highway 2012 with a couple who had an Airstream extended body Sprinter on a 2500 chassis and a cargo carrier and two bicycles on the back.
Great West Van from the get go built on the 3500.