Ive found two recent cases in NY.

http://www.nydailynews.com/new-york/nyc-...ticle-1.1889347

http://www.nydailynews.com/new-york/broo...ticle-1.1375731

It seems to me though that the much larger operations take place in more rural parts. Im guessing you can breed and train the dogs anywhere really and then sell them to people in other parts.