Stumbled across a couple of interesting suppliers while doing some research:

Edison repro bulbs:
http://www.ferrowatt.com/

32 volt locomotive bulb:
http://www.aamsco.com/light-bulbs/railway.php

The AAMSCO company is well known to virtually all electric railway museums, as well as railroad museums. The company has done a stellar job of producing those bulbs for streetcars and locomotives. They are perennial exhibitors at the annual ARM/TRAIN meetings and advertise in the joint ARM/TRAIN publication.

Thanks!