I have an idea just strange enough to be right for a 3 speed...

Construct a short S/A cable with a threaded connector on both ends like usually connects to the indicator... Then connect it to the the main length of cable with a piece of threaded stock with the same diameter and threads of an indicator. This should be possible by cutting the head off of a small bolt.

This seems like a solution that would retain the looks of the typical 3 speed, and give you enough strength...

You could construct the shorter cable to put this additional connector anywhere on the length of the cable that makes sense.