In search of a tiny light socket

I'm working on creating a beer bottle lamp (hopefully not as cheesey as it sounds) and the piece that is still eluding me is finding a socket that is small enough to fit through the neck of a beer bottle. The diameter of the opening at the top of a standard bottle is just over 1/2 inch, so I am trying to find a socket that ideally meets the following qualifications: 1) The socket must be less than .5 inches in diameter at the widest part of the housing. 2) Has a threaded end that can be screwed on to a standard 1/8" nipple. Below is an image of a lamp that showcase a similar design to the one I am trying to configure: Attachment 39136 (http://www.doityourself.com/forum/attachments/lighting-light-fixtures-ceiling-exhaust-fans/39136-search-tiny-light-socket-bulb.jpg)