[Fat Charlie]

Yep, ideas.

I don't think any of us would need a box of 25 or 50 oddball retainers, but a big catalog of retainers can show you exactly what you're looking for and give you a starting point in getting a few. At the local hardware store. They may even say "no, but maybe this one will help."

I needed a bracket last week. Orange Depot didn't have anything remotely similar, so I typed in what I'd call it, printed the first page of Google images and went to Woodcraft. I said "I need something like this," and the clerk pointed me to where I got almost exactly what I wanted.