We've had a 93 Winnebago Adventurer, a 2004 Newmar Mountain Aire and our present coach a 2005 American tradition DP on a Spartan chassis with Allison 6 speed. All 3 performed very well in both hot and cold weather. The Winny held up well in both hot and cold weather but the Newmar had some real issues with cabinets splitting once we got to AZ. The American Tradition is a much better built coach than the other 2. So you may want to look at American Coach.
Here's another site that will give you the opportunity to get some prices.
RV Online