@Hellsing1: Dingux crashes? Does that happen for any MSX model and game or only for some? Any other actions needed to reproduce? Do you run openMSX from some kind of menu or from /usr/local/sbin/main?
I haven't had any OS crashes myself, only filesystem corruption once in a while but that's a known issue of the current Dingux releases.
I'll take a look at the Spectrum emu's virtual keyboard.
X just happens to be space under Dingux and openMSX doesn't remap it yet. If it were only about labels, I think A would be the best choice (space and joystick button A typically have the same function), but it's so close to the side of the case that's it not a good place to rest your thumb on. B is a good choice and it's consistent with the European PSX mapping.
@Reo: We have a big game database included already (see softwaredb.xml), we could add something there. But I'd prefer to have categories and a reasonable default so we don't have to add info separately for every single game.