Ebay - it isn't really the non-latex part it's how thin the okamoto/sagami are 0.01mm is almost like not having anything on, "almost".
Edgewater Mitsuwa / TESO in NYC 31st/broadway are the closest that I was able to find by NNJ. (mitsuwa being hit/miss on if they have any in stock, TESO has tons)
Once you goto the japanese ones it is hard to use others. BTW the okamoto's are lubed and are a touch smaller than the sagami 001s. Getting them on takes some getting used to too, sometimes it rolls over itself and you have to finagle with it to get it on.