Hi Tony, do you mean for a vitaloni trapezoid type external mirror? I really wish you good luck... however, on these mirrors it is the only one part always wanted from all so, in case someone has one good means he has also a good mirror! I guess you might be asking for a new (rear and expensive) or just a good used one mirror. My 2 cents...
Yes I do mean the trapezoid type, I was hoping someone had an old broken mirror with a good gasket. They were purchased them from IAP (about 2 1/2 years ago) and called them and they said they don't carry the mirror anymore (but there in the brand new catalog) anyway just a shot in the dark.
New repro trapezoids still existed not so pricey anyway. Originals are rare and expensive. I know people (including me) bought the new repro only for the surround gasket so to restore the old original vitaloni! It couldn't be elseway if you want to have the original in great shape. I was about the same issue some years back and finally ended up, making new green glasses for these mirrors, too. The problem is the new gaskets from the repro mirrors that are not exactly the same, quite different plastic material, but works in general. Also found that these green custom glasses are not so common these days and my glasses were thicker (I guess 4mm instead of 3mm) , they can be fit but with some difficult, although new glasses are exactly of the same appearance and much better comparing with the original. And because of the new glasses tightest fit seems that the gasket provides now a better sealing, too.
So, I might have some spare glasses and maybe also have one new of this grey repro gasket if you are of an interest. Probably have one complete restored mirror, with new thicker glass and new gasket (from a repro mirror), while the rest mirror remains original. Need to check , but not before next Monday, send me a PM as a reminder