bike habitat and bikeworks probably have those hubs in stock. give em a call - BH is (212) 625-1347 and BW is (212) 388-1077.

if you have some more time, you might also check out shops like sids bikes on 34th (bt 1st and 2nd, i believe) and conrads cycles, on tudor city pl (follow e41st st east past 3rd ave,up the hill). not as much fixie stuff there, but very knowledgeable shops with nice stuff.