Kozlik's is amazing, the best mustard we've found in traipsing around the world. For a while we lived across from the St. Lawrence Market in Toronto, and had the full selection available to us at their stall in the South Market. Then we went to Brazil, which was a Kozlik's free-zone, sadly. Singapore was better however, and we were able to get a couple of varieties there, especially the maple-infused one which works so well as a base for a vinaigrette for arugula.
Now we are in Calgary and have found some here as well. Life is good.