The strap i have was made by someone in the German Pagoda Club. Douglas Kim received it from Achim. Another source Doug mentioned was Ollie Dare at Dare Classics in Elk Grove, CA: ollie@dareclassics.com
Interesting additional note from Doug Kim... the luggage straps came in both black and brown. He's seen both brown and black straps in orginal cars. (I'm tempted to look into having mine dyed black, or finding a black one...)
Craig