This is OT, but since you know a lot about the hardware revisions, there's a mystery that has confounded me for years.
A friend of mine owns a game shop, and one of the old Genesis consoles he bought from a customer uses a different style of connection for the RF jack instead of the typical RCA. The only other time I've seen that type of jack, it was on a shitty famiclone that I bought in eastern europe.
It's an early model, and it came with a matching official RF box. It's not a euro megadrive or anything like that, but I have never been able to find another system like that, even online. Even hardcore Sega collectors I've talked to have no idea what I'm talking about.