Although their website may not indicate it, they can order all the Surefire flashlights and accessories, although you may have to wait 1-2 months for items not in stock.
You can order by phone and have the stuff shipped to you.
I ordered a few flashlights from them that way plus some accessories. I plan on getting the A2 Aviator from them too.
I don't believe they will sell you the SureFire batteries though.
You will probably have to pay $5/each for whatever brand they do sell.
I've seen their website. How are the prices? They don't seem to list any prices on their website. I'm just thinking whether it would be worth my while to order from the US or just to order from them.
For instance, on a $120 USD item I paid $212 CDN. So that's basically just the exchange rate plus a few bucks. If you factor in courier shipping from the states, it could be cheaper ordering from Nicholls.