I've never tried to find amazake in Toronto, but have you tried Sanko foods (
http://www.toronto-sanko.com/)? It's been a while since I've been there, but they import quite a bit of Japanese food, they may have something. Not sure though.
Another place I guess you could try is Heisei Mart in the J-Town mall (
http://www.jtown.ca/English/index_e.shtml). I've never been there. I used to live around that area but moved before that place opened up and I haven't had a reason to go there.
You could probably give those places a call just so you don't waste your time going out there just to find out they don't have it. If you've already tried these places, my apologies. Good luck in your search.