I'm surely not ignoring ISO as a personal hit to anyone. It was actually included in my first render of this when I proposed it to the important parties needed to make this happen. As it goes with everyone set I'm trying to balance cost and keys, for everyone interested, and it was decided that it simply added a good chunk of cost and benefited a minority of people that would be joining more than likely. This is also likely one wasn't added to the original kit as well (though that is an assumption, I don't know that for fact).
I don't personally use ISO, but if there truly are that many limited keys out there maybe one of the UK group buy sites would be willing to run a drop of just enter keys of various colors, much like people have done with ESC keys in the past.