Thanks for the correction. I was thinking of the latter situation, but did not consider that it would not also work for the DITB's need. He will need a custom solution, as you point out.
GSP
Maybe not a custom solution, but a ready-made cable (which are yet, hard to find)
I found a cable which seem to work (see above), and several people have also made their own cables/adaptors, or have had them made. The issue here is that you would be connecting a tethered charging station cable to another cable, rather than directly to the car. No matter what quality such cables/adapters would be, any technical problem (or even a fire) would for sure be scapegoated onto the cable/adapter of the non-J1772 car, regardless of what caused the problem.
With all these standards floating around, it's
a disgrace that one at least cannot have a decent adaptor. For the good of all EVs, the more charging possibilities, the better for the entire community. Imagine if you couldn't SMS or call between iPhone - Android - Nokia and other standards? That would be quite annoying. I wish that all cars could use all chargers, and will attempt to make my car able to charge as many locations as possible.
A few days ago, I was in Maritime Square (Tsing Yi by the MTR). There are three spots, all of them have 13A (which for the Tesla requires a 3600 HKD cable - which I have). Then there is one single J1772 with a tethered cable - in other words, not a socket, but a cable with that "Moon Base Alpha" looking ray gun mounted at the end. At this location, which is right next the the entry/exit AND the parking warden, she told us
"This is the first time I have seen any electric car try to charge here". Go figure. If no-one asks for charging, the infrastructure won't be made any better.