They are not hard to find. Local parts gurus should be able to get one easy enough. If they know what they are doing.

Also, lots of tractors with air conditioning use them. Coach builders for school buses and RV's use them. Semi trucks use them.

Got to find someone that will look in a book with blower motors illustrations and measurements instead of trying to look it up by application on the computer.

Sources: Local parts stores, tractor repair and truck repair centers, RV repair shops all should be able to get a dual shaft heater motor easy enough.