I was lucky enough to have found a NOS Servi-Car tow bar safety cable assembly, Harley part number 82260-39A, and decided to copy it and make a few to sell. They are pretty much identical to the originals: 1/4" steel rope, spring hook clip on one end and a 9/16" mounting stud on the other w/nuts, the cable length is 60" and the protective hose is 55". The biggest difference is the spring hook clip, they don't make them that large any longer, see photo so you can see the difference between the original hook and mine.
$75 plus shipping.
$75 plus shipping.