> It's pretty hard for the shortcuts to be consistent and localized. Especially if you also use different keyboard layouts when you're using different languages...

Hence my original comment. I haven't had a problem with different keyboard layouts, since most of the keys that change are on the outer edge, nowhere near where the most common shortcuts are located (then again, I rarely type using QWERTZ).

> Even for keys that aren't mnemonic, do you want undo to be ctrl + z or ctrl + the key closest to left shift?

CTRL+Z, since that's what it's been since time immemorial, even on ISO keyboards. Consistency is king.