The closest one is in the NM at Westchester Mall in White Plains. However, I've been to that one, and I'm personally not impressed.Are there any authorized retailers in CT (specifically in the Darien/Greenwich area)? I was surprised there aren't any boutiques.
If you are going to drive to White Plains, I'd make the full hike down to the city and go to the 57th store.
That's just me though. There is parking really close by, just one block down, on Madison and 56th, NE corner.