+1 on Altman Luggage. They don't carry a lot in stock but can get you any current Tumi and will "work" with you. I've bought more than several pieces there going back about 15 years.

Ambassador Luggage on 45th and Madison has a fantastic collection of Tumi in stock. I've come close to buying from them too but haven't yet done so. They have hinted they would negociate.

Some FTers have reported buying at Macys with one of their discount passes but every time I have looked at one, Tumi was listed as an excluded brand.

There are a bunch of Tumi stores around Manhattan including one in Grand Central Terminal. I don't think they would ever discount unless Tumi was having one of their sales -- and after a bad experience with an obnoxious saleswoman, I don't think I would ever buy from them (not sure if a company owned store or franchise). (The reason I think it may be a franchise is the salesperson told me all sale items were final sale -- and she also said that was normal for the industry, which is rubbish. That wasn't the only issue but not worth elaborating.)