You'd need a deal with a chain to build bikes, too. Some people can build a bike, but fine tuning them is a skill. Local Bike Shops can and will charge $50-$100 to build a bike that isn't bought from them. If you're trying to sell mainstream at the $450-$650 price, that's a decent extra charge.
Sport Chek, btw, employ decent bike mechanics, and have a wide network of stores. Would likely be hard to strike a deal with them, though, seeing as they sell their own bikes.
Anyway, it's something to think about, and IMO, the biggest drawback to buying a bike online.