Having seen several references to interest in these cars but not finding any recent discussions regarding production, I wrote to the only maker that came up on Google as having been interested, Island Modelworks, and received the response quoted, in part, below. I suggest that anyone having an interest email these folks at info@islandmodelworks.com to indicate their support. I apologize in advance if this issue has been addressed in the past, my only excuse being that I'm new to the Forum.
"We had attempted in the past to produce this model, however, we
couldn't generate enough interest from people willing to place a deposit
on a non existent model. We only needed enough for about 25 - 30 models.
if you are serious about ordering ten of them, we will put out another
request to try and generate interest in more of these cars. Yes, they
would be designed to fit onto the MTH chassis for ease of powering them
and we may offer a complete kit if interest warrants it. We would modify
our HO scale version to fit o scale and add more detail."