The updated Nexus 7 has already started shipping early in the US, but our kindly neighbors to the north haven't seen a mass influx of Nexus tablets yet. There is at least a trickle today as Staples, Best Buy, and Future Shop are beginning to show availability.
Staples is still selling orders online with 1-day shipping. Most stores are also showing it as in stock. Best Buy is sold out online, but a few stores still have units available for pickup.