I'm going to sneak in here with another thought:
Consider a diesel pusher RV built on a bus chassis (GMC, MCI, Prevost, Eagle, etc., but NOT on a school bus chassis).
Why?
Do a Google Images search for RV accidents, or ask any paramedic that's had to work the scene of a typical RV collision accident.
What price SAFETY?
FWIW & HTH. . .