Tying up loose ends ...
I was able to repair the DIN connector. It is not museum original
anymore, but it works. The details (with pictures) can be found here:
http://www.brutman.com/IBM_PC_Keyboard_Plug_Repair/IBM_PC_Keyboard_Plug_Rep…
The short story is, the plug comes apart. Get another DIN connector,
hollow out the original IBM housing slightly, and then connect up the
innards of the new DIN connector. You can make a pretty decent looking
repair this way.
Mike