mercedes long body sprinter

The extended body 24-1" Sprinter has a 170" WB the same as the 22'-9" RB Sprinter. Advanced RV, Great West Vans, Sportsmobile, Winnebago and Airstream have extended (or long) body Sprinters. Roadtrek, Pleasure-way and Leisure Travel Vans don't offer the longer Sprinter.

Here is a link to the Sprinter Forum which lists all manufacturers using the Sprinter chassis: Sprinter.
Also look on the Class C forum or do a search for Sprinter on the B and C forums.

There is a 176" wheelbase (~22 feet long), and a 176" wheelbase extended (around 24 feet long.) Roadtrek and PW use the 176" wheelbase one for their primary sellers, while Winnebago uses the 176" extended body for their ERAs. Airstream uses the 176" for their Interstate, and the 176" extended for their Interstate EXT model.

I think you will find that there are a good number of happy owners of these vehicles.