If you can head to GTA West (Mississauga), you can go to King's Vegetarian and they have lots of seitan variety. They supply all the Zen and Kings vegetarian restaurants in GTA. I find the taste really good.
Thank you for this recommendation - i had forgotten about King's but coincidentally I went to one in the city the day you sent this and came back with a bagful of mock-meat groceries! Veggie gumbo, here i come!