It's no longer a rumour. We're currently watching the closing ceremonies for the 2012 Pokémon World Championships and the location has been revealed to be in Vancouver, BC, Canada. It will likely be at the Vancouver Convention Centre on August 9th to 11th but nothing is known at this time. This is the first time that the World Championships have been held outside the United States in its 8 year history! If you're from outside Canada, remember to get your passports in order because you'll need one to enter.
If you're reading this post and are unfamiliar with the World Championships, it's an invite-only tournament featuring the best Pokémon players from around the world - about 9 countries for the video game and dozens for the trading card game. There's also a last chance qualifier tournament held at the event for those who don't have invites to try and make it into the main event. For those not interested in the competition, there is rare and unique merchandise sold at their merchandise store, autograph signings by the creators of the game, side events, and plenty of ways to spectate the high level matches.
Update: The event is now confirmed to be in the East Facility of the Vancouver Convention Centre inside Canada Place from August 9th to 11th just as we predicted. The Fairmont Pacific Rim Hotel is connected to it which may well end up being the Winner's Hotel. For those looking for other options, there will be plenty of hotels with easy access to the venue as it's downtown right beside a major public transportation hub.