Looking to spend between 20-50k. any recommendations?

In my opinion you cannot bet the quality of an "older" high end Motor Home.

Parts are a little harder to come by but there are a number of salvage yards.

The point though is the parts used in the high end coaches last and you are not repairing them as often as the newer cheaper built motor homes.

Here is an example of a Prevost http://www.rvtrader.com/listing/1988-Prevost-Country-Coach-Mirage-113921482