"The CMC Speedster I had was supposedly one a few built in house by CMC for a special customer."
I've heard that, from time to time, about a few other cars, and from the information I got while sueing the hell out of CMC back in the mid 1990's I can tell you that it is a myth. CMC never built completed, "turn-key" cars in house. They weren't equipped for anything like that, nor did they have an in-house car building department. Bodies and parts, yes - Completed cars, no.
They used a couple of autobody/custom shops in the North Miami area that would do builds for them, even some custom builds like yours (which is super-cool, btw), and charged the customer exorbitant prices for the "Custom Assembly work". Those two shops were kept pretty busy for a few years but only produced 30 or less cars, many of which ended up in Airport terminals as sales attractions (many without engines).
I also uncovered another shop like that up in Raleigh, NC doing the same stuff on a more limited basis (small handful of cars) and suspect there might have been a few more shops around the country in more populated areas.