Somebody on here has done this before. I think that it was Horvath. He used stock front parking lights with clear lenses and a clear bulb mounted below the tailgate. It looks factory. Do a search for a thread on back up lights. This has been discussed before.

Here is the page on his website that addresses this: http://www.alanhorvath.com/54chevy/backups.php

Never hold your farts in. They travel up your spine and into your brain...that is where crappy ideas come from.