Where to find bulbs for mini turn signals

[trumpetguy]

The previous owner of my bike put on miniature "carbon fiber look" turn signals.  One of them has a burnt out bulb which needs replacing.  They seem to be made of unobtanium.  It's a mini-bayonet base, and has 12V 28W on it (but no bulb number).  The glass part of the bulb is elongated compared to all the mini-bayonet bulbs in the (auto) parts store.  I can't find any such bulbs online.

For now, I replaced it with the brightest mini-bayonet base bulb I could find, but it's dimmer than the other side.

Does anyone live in a metropolitan area where a shop sells these signals?  Do they carry the spare bulbs?  Will you please post their contact info?