I bought mine used without a S42 remote unit. So I had to build something functionally similar (which took me much longer than anticipated). It also came without a cable. In order to keep costs down, I bought a 7-pin tube mic cable and changed the connector on one end. My DIY-S42 remote has a 7-pin XLR connector. I have a feeling these connectors were used to make AKG's stereo mics compatible with Neumann's SM69fet. Although I'm not 100% sure the Neumann remote supply works with the C422. In any case, my mic has 18V Zeners that are not in the service manual schematic. Of course they may have just forgotten them.
Anyway, it's intersting to see that there are more of these "mutants" around. I met Tim Campbell at last year's Musikmesse, and he had a C422 with the original connector. He said that connector is notoriously unreliable. So I guess we should be happy to have the larger, more robust tuchel connector.
Yes, too bad, AKG dropped the stereo mic line. Supposedly the later C426 was even better. You see them in one of the old ABBA videos as a dual vocal mic with the girls facing each other. Beyerdynamic had an LD stereo mic, too, but that one was discontinued quite a while ago.
Audio-Technica just released a new stereo mic based on the AT4050. Maybe there is hope for a stereo LDC renaissance.