I have seen the singles in both Walmart and Zellers (in Canada).
They are a little bit smaller than the old "Ponyville" ponies. I don't think they are intended to be anything more than cute little figurines. Pretty sure they have discontinued the Ponyville line of toys, unfortunately.
Unless, that is why Fluttershy was left out, and they have some big, awesome playset planned for her. But I doubt that.
Anyway, my daughter uses them with her Ponyville stuff, so the size isn't THAT big of a difference. SOME of the PV accessories work with them, others do not (shoes!! Their hair is molded right to their legs/feet/bodies, so they often can't get the shoes on)
Oh, they seem to go for about $3 up here.
I hope the blind bags make their way over to Canada/USA. My daughter saw a picture of them and wants them... and I want Fluttershy and Minty!