There's a coleman outlet in Lake George which is where I buy all of my fuel (I have the "xtreme" version of the stove and love it despite trying to find fuel)
Last time I was there I also found that they had an adapter for the fuel that you could attach the normal butane canisters to the stove (in an inverted manner), but it was $30, but might be useful when you're going into an area that might not have that brand.
Seems to me that I saw some Coleman Powermax Fuel in REI (Reading, MA) a few days ago. Doesn't show on the website, perhaps because they can't ship it to your home.
Didn't see it on the EMS website, but a call might find it in a local store.