She was released in the United States; not sure if she was sold elsewhere. I would guess she would only be found in the US, or most prominently be found in the US, since AFAIK Hasbro only expanded the MLP brand to other countries after it was such a hit in the US.
I got one a long time ago from a lot with some random Pretty Parlor parts, like one wall and some accessories. The funny thing is I didn't even know she was flat-foot, I just wanted a new Pretty Parlor door. I don't remember which state it was from, but definitely from the US.