Well number one I would BUY it from Costco no matter what.
Cant beat the warranty as you can literally take it back for a full refund probably more than a year later.

I assume AJ Madison might have them in showroom, they are in NYC.

What Trevor said about margins is also in a thread from a couple of months ago. Margins on those stoves look too thin for stocking a floor model unless the dealer is selling a lot of them.

But, you might be able to find one for viewing by checking out real estate listings. I saw one ad here the other day that mentioned having an NXR stove, so maybe something will turn up for Boston in a house you could go see.