Too bad you couldn't get the i3 medallions and grind/file them down to fit. Couldn't you fashion something out of metal to fit and epoxy in. Something that would be easy to cut, then grind, and stack until you get to the outside of the housing. Not sure how uniform the opening is?
I'm thinking of the last Wishon head where I had the tiny little medallion fall out and I made one out of a soup can top. Tedious as hell but it worked and looks OK.
Or what about these-
I suspect you could cut to size and fill in where the medallion was. Only ? would be if it would be too thick and stick out and catch on something and fall off. Might be able to add a little epoxy so it holds better. Or if it does.not stick out, fashion something to go over it an epoxy to the lip of the housing to cover it up.