I imagine you can run the wiring in a zip conduit up the stake picket and drill a hole w/ rubber gromet that would pass the wires into the round.
To keep the period look, how about a set of '53 (Don't remember what '54 look like but maybe they would work too) front running lights?
<a href="http://www.oldchevytrucks.biz/c/g8/p/b060f.html" target="_blank">http://www.oldchevytrucks.biz/c/g8/p/b060f.html</a>
[ April 26, 2003: Message edited by: willys36@aol.com ]</p>