I talked with Marcus on the phone today.
He said the the Guardian was made around 2000 as he and his sons were getting back into paintball and playing on High Anxiety out of Florida. He estimates around 50 were made.
I'm sure we will find another eventually and when we see the serial number on the next one that pops up is we can get an idea of the production size.
Marcus said the Guardian was a great paintgun and had a few changes from the Falcon but it couldn't keep up with the electronic competitors so he made a few for the players and wanted them but that was it.
Thanks again Rick for finding the Guardian in the first place.
And Chris, Marcus did seem interested in semi kits for nelsons, he asked me if I knew anything about the kit Line SI showed in their ads (c.1988 predating the double action) and told me about the Scorpion Autoloader and Chameleon kits he had seen. I didn't ask him if he ever made a kit though since I guess I hadn't read your reply to this thread.