Well, I know Ben Silver does real gold monogrammed blazer buttons for ~$1K, but that's probably not what you're after... It's a coincidence that you posted this just now, because not 5 minutes ago I received a "Nordstrom single-breasted 46L" navy wool overcoat I'd bought on ebay. Nice pick-stitching details and peaked lapels. I put it on, and the shoulders felt like a vise while the waist was impossibly large. I looked again, did a double-take at buttons sewn right on top of buttonholes
, and eventually realized it was a German
46 DB that somebody "expanded" to an SB.
I need to find about 4 more buttons to restore it to its original state, after which it can make one of you 38L or 40L beanpole types happy.