D3X, D3, D700 are made at the Sendai plant in Japan. Not sure about the D300. All the other cameras are made in Nikon's Thailand plant.
NikonUSA's policy is that grey market imports have no warranty -- in fact they say they won't repair a grey market item even if you pay them.
If you buy a NikonAsia-imported camera while you are IN Taipei, that isn't grey market.