Hey Deryck (and others with the same question),
Thanks for posing this. I can't give you any hard numbers to put down in your application, as we're still in the planning stages for this Wikimania. More info about the exact prices of Wikimania will be available when registration goes live sometime in the late spring.
What I can tell you now is that registration costs will likely be similar to Cape Town, but will be raised slightly due to Stockholm's more expensive nature. As for the hotel, we will be offering a similar booking situation as last year, where we partner with a hotel that provides a number of rooms at a discounted rate when booked using a specific code or via a specific link - those rates will likely be between 1250 and 1350 SEK a night.
Thanks much,