Interesting that Field Van can't assist with a replacement. If you can't get in touch with SMB South try SMB North (260) 356-5435 closes today at noon. Could also try replacing the hinges that broke? McMaster-Carr has a huge selection. Not sure how the originals were attached on your door, but if welded - any welding shop should be able to attach owner supplied replacement(s). Of course then you'll need to repaint...
2001 Sportsmobile RB50 7.3
West Central Mountains, Idaho