Steve:
You mentioned the only plates I know of. I started making these a couple years ago when there were none available. I have heard that Brownell's is carrying one but whoever told me that was not too excited about the quality. I have not seen one and am not even sure they still exist.
My plate is roughly 5-1/8 " high and 1-5/8" wide. Those dimensions are pretty close to the original Parker plate that I have here, which I gather is a "medium" sized plate. I know there is a larger one, and apparently a smaller one. In any event, if the dimensions work for the gun you have in mind, I can find some kinda way to move the top bolt hole up and make it look like a Parker plate. It will be mostly hand work but it can be done. Feel free to contact me direct.
Best regards,
Glenn
gfewless@tds.net