I found a pristine genuine vw topcable.... I have the pic's and the measurements for you...

That is a steel outer sheath crimped to the end of the cable.
The sheath has a width of 1/8th of and inch and is about the same size as the cable itself.

The total length of the rear cable is 94 inches long from end of bolt to end of bolt.
The rear sheath is 40 inches long.
The cable is 27 inches on either side of the rear cable to the end of the bolt
The bolt is 2 inches long and the treaded part is 1 1/8th of a inch total.
The bolt is 3/16 inches wide.
Now with all that information we can manufacture our own rear cables that are structurally as sturdy and the same dimensions as the genuine VW cable at a 1/8th of the cost.
So for all you folks that don't want to bother and want to pay the 40 to 150 for a new rear cable, and IMHO the TMI cable is a crappy one. Just make your own and send me the difference....
So the operative word is that the cable is only 90 inches long. the bolts are 2 the sheath is 40.... Go forth this spring and replace...........
For outer sheath you can use brake line and run your cable through the middle.

Enjoy