Pat,
The last that I heard, BCS (Beaver Coach Sales) was stocking parts for this shower enclosure with the exception of the door. Another option would be an RV salvage yard, especially if you have a broken door. These shower assemblies were used in some Beavers, Monaco, Country Coach, Foretravel, Newell, and Prevost conversions. So there are a lot of them out there in high end coaches if you can find one in a salvage yard.
Gerald