Online Store and Store Location Stocks
First of all, I wouldn't consider the Playbook price drop a "firesale", rather more of a way for Rim to get more Playbooks out of the shelves and into the hands of consumers. That said, I have done a little work to check the status of the Playbook sale numbers at Futureshop and Best Buy.
Both sites say they are out of stock in their online store. And after doing some actual store stock check, quite a few locations are out of stock. Hopefully this is a good sign that the sale is working and Rim can get the numbers up closer to where they want them to be and make the masses happy with the OS2 release.
I posted a few screenshots, but feel free to add locations in your area if they appear to be selling out. And it doesn't have to be Best Buy or Futureshop. I tried Staples but didn't see a store stock check option.