No I have not. I did buy a Edwin Jagger for the handle and the head had some rough places. It looked like it was handled a little rough.
My Cooper razor has some damage on it. Not sure it is zamac. I'll take some pictures tonight and see for sure.
Both my Clix and the Cooper are raw/unplated zamac, and were used before I got them, but neither shows any sign of what's described as rot. Have read that it depends on which formulation of zamac is used...some mixes are much more corrosion-resistant than others and that under certain conditions zamac (like aluminum, which it contains) can develop its own protective coating. Since both of these were likely made by/for Cooper, maybe they used the good zamac mix. I hope so but time will tell.
I have an old grafco open comb. It had some flea bites on it when i got it. They don't seem to be getting worse, but i don't use it very often. Primarily, because i don't want them to worsen. I had to edit, because i misnamed my grafco an adams.