What you are describing sounds like the Disney "Retlaw" coaches, a bunch of which are now owned by Rob Rossi of San Luis Obispo County. There are also a combine and coach constructed for the West Side and Cherry Valley which are currently resting in Placerville, CA. Maybe the historical group there would trade them for something with more of a provenance. If one were to build brand new (small) 3' gauge cars, why not pattern them after the Laconia or Billmeyer and Small cars built for the eastern 2' Roads?