If you went to an Apple Store in Canada just yesterday, they would have limited you to just two unlocked iPhone 5s per transaction and a total of ten unlocked iPhone 5 units per lifetime. However, you can now buy more, as that limit has been lifted. Now, they're letting you buy up to 10 unlocked iPhone 5s per transaction and an unlimited number in your lifetime. I guess they're ready to address the holiday demand for the newest iPhone, though the rumors of an updated iPhone 5S for next spring may hinder some of that demand.
Should you choose to do your iPhone shopping through the website, the Apple Store online lets you add up to 999 unlocked iPhones to your virtual shopping cart, but it won't let you actually complete a transaction with more than 10 iPhones in there. That said, nothing's stopping you from having multiple transactions, though I'm not entirely sure why an average Joe would want to have more than 10 unlocked iPhones in the first place. I guess that's your prerogative.
As an aside, sales of the new iPad mini are still restricted to two per customer.
Via iPhone in Canada