I'm late to the party, but wouldn't it be useful, if this article is mainly aimed at designers, to point that the differences between ANSI and ISO go a bit farther than just the 4 dark blue keys depicted here ?
I'm not talking about the number row, since it's a lot of pain, as you noticed.
The problem lies with the letter caps, more specifically AZERTY, QWERTZ and whatnot.
I'll take AZERTY as an example: the main differences with QWERTY are obviously A, Z, Q, W and M, but you can't swap them around since they are from rows of different profiles...
You might not want to mark all the possibilities in dark blue, as it might be confusing, but maybe it's worth pointing out somewhere ?