Okay, I hate to have to enlist my army of readers yet again, but maybe one of you owned the US version of the Technics SU-C01 preamp back in the day and have this little beauty squirreled away in a box somewhere. It's a proprietary (although strictly speaking not required) connector cord for the C01 micro series components that came out in 1979. Sure, you can connect the tuner to the pre-amp to the amplifier with regular RCA cords, but this was always a much more elegant solution.
I found one source online that had the part listed (SPJ9401), but when I actually went to order, it came back as discontinued. I just missed out on not one, but two Yahoo Japan auctions for the thing, so I'm hoping I can locate one somewhere else. Maybe one of my thousands of readers?
I sold my previous set of C01s (with the connector) ten years ago to a friend back east, and he thinks he still has the part and is willing to sell it back to me, but he recently moved and is occupied with more pressing tasks than rummaging through boxes to locate it. Interestingly, before shipping the components to him I thought about keeping the cord just in case I ever got another set because I knew it would next to impossible to replace, but ultimately decided to pass it on.