http://www.gdcc.ca/breeder.html
This is the website for the Great Dane Club of Canada, they have one GD breeder listed there. You may want to try
www.petfinder.org, you can specify the type of dog you are looking for, and where you are located, and they list the dogs available (that's where I found my dog) but bear in mind these are rescued dogs either with foster homes or in shelters. Some are purebred, but are not with their breeders currently. (at least I think most are in shelters!)
I'm still on the lookout for you though, all the way from Ontario!!!