OOH, a fellow Canadian! Not many of us on here!
I've had a hard time finding canadian sites as well - I've paid a small fortune in customs fees from ordering things from the US.
Here's a couple links to Canadian sites...
www.dogfatherandco.com (toronto, Ontario)
www.johnandrewforpets.com (toronto, Ontario)
www.renspets.com (oakville,Ontario)
www.barkandfitz.com (oakville, Ontario)
www.peculiarpets.com (B.C.)
www.foufoudog.com (Richmond Hill, Ontario)
www.trixieandpeanut.com is one of the best sites I've found - Not in Canada, but you get your stuff FAST and her stuff is great (she's also a YT member).
Hope this helps!