Unfortunately there aren't tons on ebay that I could find other than the ones with built in reflectors which won't work in the E2 as the reflector is part of the head, it doesn't come out separately. I know you can get replacement heads but I don't want to change the lights, just replace the bulbs.
If I can't pick up cheap drop-in's I'll probably just keep them as my 'token' incandescent lights.