Of course the obvious answer is to order one from R&S! ROFL 🤣🤣🤣.
These are made of cold rolled, tinplated steel. Practical idea: Get one from one of your "dumpster dives" and reform it with pliers and tin snips. The exact dimensions don't matter, just so it does not short out anything. Since you want to be a perfectionist, yes there are companies that would make you one, but at high costs, the main one being an expectation of a production quantity order follow-on.