As Punkin said, there are cheaper options available if you want to fly aound here without bringing your own plane over.
However, that said, I know people who've ferried various aircraft over from the U.S. 185's, 206's and 182's. If you've got the funds, the logistics are possible. Haven't heard about a 172 ferried, but it's not something I take a lot of notice of. There could have been a whole fleet of them flown over.

Yup, ferrying or shipping is only logical if you are buying something you can´t find in your location for whatever reason, exceptional price or exceptional performances. Even if you are moving, it may be a better option just selling yours at "home" and buying another one later in that other place. Just what the guy selling me the Rocket made. He moved to Tahiti from France; ferrying it is possible, but for how much!?

As for ferrying vs shipping 172´s, I guess it depends on the time the operator has. Those ferried to Spain had to be here ASAP, so they flew it. With some more time and considering it was quite a few of them, maybe shipping would have been cheaper, but it´d have taken a lot more time also.