The rare 914 third brake light has been found and is now on eBay:
http://cgi.ebay.com/ebaymotors/ws/eBayISAP...&category=33716
I asked the seller from what type of car it actually came from and I was told a '73 914. He doesn't have a clue what he's selling.
It's the same light that Mark, Engman, sells in the classifieds.