I've been looking for details on import mods for the Mega CD/Sega CD (I'm from the UK, ok?), and I've been falling short on details, despite a good few googles.
As I've found so little details, I'm going to ask questions here.
If there's no easy way to do it in hardware, is the lockout controlled by the BIOS in the CD unit? If so, I might see if I can get hold of alternative BIOSes, and blow the three of them into a single EPROM/FLASH, and add a selector to choose which BIOS it should be using.
Of course, I'll have to get hold of a megaCD unit that can be sacrificed first!