You need to look harder The bakery in Grand Central Station has them, as do a lot of the delis in Manhattan. When I visited my cousins out in Garden City around St. Patricks Day, we had green and whites from a bakery there.

My dad has found a place over in Sonoma or Santa Rosa where he stocks up (guess I should find out where so Magic111 can stock up, too). The only time I've seen them outside the U.S. has been in the underground shopping arcade that connects to the Munich train station, where they were called Amerikaners.