I know of three that I have seen that rolled and supposedly they were driven away after put back on the tires.
Prevost, Newell, and Wanderlodge. The Prevost and Wanderlodge were/are made of Stainless frames.
As Doug stated, they are not cheap, but the Prevost and Wanderlodge that I rode in were a very smooth ride.
The Prevost and Newell you should be able to find all the parts you need, The Wanderlodge is out of business and parts are becoming harder to find.
http://www.marathoncoach.com/--11_Great_Things_About_a_Prevost_Shell_You_Might_Not_Know
this is just one place that has that Prevost frames are SS. Prevost site also has the same info