Student88,
There are two Bose stores in NYC that carry the full line of consumer products, as well as the aviation headsets. I just called both, and was told the A20's should come in about two weeks (I'm considering dumping my brand new Zulu and switching to Bose, so I was curious). One is in SoHo (downtown NYC), and the other is in Columbus Circle (midtown). However, obviously you won't be able to test them side by side against other brands. The Bose stores in Manhattan NYC:
465 Broadway
New York, NY 10013
212-334-3710
10 Columbus Circle
New York, NY 10019
212-823-9314
If you're looking for a pilot shop, the closest pilot shop to JFK is
The Original Pilotshop, located about 20 minutes east of the airport. However, I don't believe they carry the Bose line at their store. There may be an FBO at Republic Airport (KFRG, about 45mins east of NYC) that carries them, or possibly at Westchester airport (KHPN, about 1hr north of NYC). After that, you could try at Linden Airport in NJ (KLDJ, about 45mins south of NYC).