As a resident of the U.S. I've seen Tauros a-plenty (though admittedly lately they seem to be lacking). And then I had a trip to Cancun planned, so of course I was on a mission to capture the regionals for there, whilst attempting to appear more engaged in our actual activities as opposed to my silly Pokemans hunting.
That said, I am happy to report I caught at least two of each regional (Heracross and Corsola), but sadly none have impressive stats. Still, I filled out some hard-to-find pokedex entries for them, and have some in reserve for when/if trading happens.
Also I managed to capture a few that aren't region-locked but that I also didn't previously have, and hatched a few pros to replace existing ones I had.
The sad part is almost all of the ones I captured there show a location of ",,Mexico" – I guess PokeGo isn't all that great with the google maps API.
I also tried getting a picture of some regionals when at the ruins of Tulum, but it's actually hard getting cool stuff in the background when the critter is off the path you're allowed to be on, so can't really shift the angle for the AR photo. Would've loved to have a picture of my first Heracross at Chichen Itza.