All,
I began the process of replacing the interior plastics of my M20M earlier this summer. I pulled 4 panels and brought them to Vantage Plane Plastics. They said they were willing to make molds of my panels to produce replacements, but on arrival to their factory, they said they already had molds for most of my parts. When they sent me the replacements, they were close, but didn't fit. I suspect the round window panels were for an M20J/K or something.
Now they seem unwilling to make additional molds for my airplane. So, I intend to produce my own. I will start small pieces vantage also doesn't produce and scale up. Parts will be molded in a plastic that meets the requirements of FAR part 23. Here is a mold for the first piece, it's a cover for the luggage door inside release. Will post updates as I go, let me know if I can help you with similar pieces.
Dave Castor