That's a sweet bike, and my guess is that someone had their eye on it for a while and waited for the right opportunity. It sucks to have to be this way, but I never take my nice bikes anyplace where they can't be with me. At night they're in the house.
I know people who have diligently locked up their nice bikes, were gone for only a few minutes and poof... come back and the bike is not there.
I'd definitely go to, or call every bike shop in the area (yeah, I know it's NYC) and have them post a pic and an explanation. Do the same on Craigslist. A bike that distinctive is going to be seen by someone.