Right now, you can't purchase Chromecast in Canada, and that usually means that Google won't get around to letting Canadians use it for years, or ever. For example, Google Music, Google Voice, etc.
Well, even though I am from Canada, I went ahead and purchased a Chromecast on Amazon and had it shipped to an American address. You will be happy to know that the product information pamphlet doesn't say anything about it not working in other countries. More importantly, the last two pages are dedicated to information about how it is compliant with Industry Canada regulations.
Here is to hoping!
Just to make sure all you Canadians know -- Chromecast works excellent in Canada.. there are no regional restrictions once you have the device. The only thing you need to worry about is getting one. Oh, and it's freaking awesome! Best $35 ever spent.