Writing as a Canadian, I can only apologize for the difficulty so many of you are having in obtaining visas to this country. I am really looking forward to welcoming many of you to the beautiful city of Montreal, and I am devastated to read that so many people seem to be being turned down for visas.
The decisions for locations for Wikimania are made about two years in advance - which is actually pretty late for large international conferences (most international organizations make these decisions 3-4 years in advance). But even during the course of two years, some circumstances can change significantly. I am aware that Canada has become more stringent in handing out visas, as have many other countries in the past 2 years - something that couldn't really be anticipated at the time the decision was made. I don't have any good advice for any of you on this - while I live in Canada, I'm not a member of either the Wikimania planning group or Wikimania Canada, and I have no contacts in the federal government that would be helpful in getting visas.
I am hoping that some magic can happen for you that will enable you to come to Canada. We will all be losing the value of your company, and you will be missed.