Guy from New Jersey here. Love trying different brews - some of the ones mentioned here sound great, have yet to see a NZ beer at the places I frequent. If anyone knows of any that are available in the New Jersey / New York City area let me know.......
They are definitely around, probably more in specialty off licenses rather than in bars, apart from a keg here or there - I don't know New Jersey or New York however.
If you can't find NZ beers, then plenty of US beers use NZ hops from Nelson, Mamoth Brewing Company from California also brews in collaboration with some NZ breweries to create limited run US/NZ hybrids.