One can be added like they have done in this motorhome below.
Freestanding Fireplaces for Use on the Road
Some RVers enjoy the portability of free standing electric fireplaces, styled like cast iron stoves. These models offer the convenience of no mess nor clean up after enjoying the flame effect. There is no need to wait around to make sure the fire is completely out before going to sleep or leaving the RV. The flexibility of an electric fireplace allows patios to be warmed on clear, crisp evenings, moved indoors to heat the RV sleeping area, then unpacked and placed into the owners home once your trip ends.
If you have pictures of a Newell Coach with a fireplace added please post one. I'd like to see it.