My wife in I were just in Montreal for a few days. Scanning a Jewish newsletter, we found a kosher sushi restaurant had just opened. It is called "Sushi Mekomo", and it is diagonally across the street from the Villa Maria metro stop. The sushi was pretty good and reasonably priced (a boat for two was $31 CAD). Though they did not have any non-sushi main courses, they did have an amazing chocolate cake for dessert. The place was non-descript, and they are still getting their act together (some of the appetizers weren't available), but it was an excellent meal overall.