Maybe it is about time you undertook a project to have these made. It is fairly simple and straightforward. You would get to have the fun of dealing with vendors, carrying the inventory, selling, answering alot of questions and developing new penpals. One chap made these about 17 years ago–but they are all gone. I am sure you could sell 10-20 of these.
I have a good used retaining ring. Give me a call,also have molds for Multibeam left and right 33-34 headlight lenses. Give me a call on my cell. 253-229-9573.