The US also has pre-clearance in a number of islands (Bermuda, Bahamas and perhaps 1 or 2 others) and has immigration pre-clearance (but not customs) in Shannon and Dublin. An agreement has been signed to upgrade the Irish pre-clearance to full Canadian-like pre-clearance in the near future.
Yes, and we frequent travellers are pre-registered so that we just look into the NEXUS machine at any international Canadian airport and whisk through US or Canadian immigration. But that's not the main reason that Toronto would be a good site. It's central, it's well connected, and as Evan noted, the visa situation is less screwed up than the US.
For Geneva, I have never entered France from the airport, but my recollection is that the airport is physically in Switzerland but bordering on France, ...
It has two entrances, one from Geneva, one from Ferney-Voltaire in France. You could go through customs within the airport if you needed to switch sides. Trains to France from the Geneva train stations were also precleared. But now Switzerland has joined Schengen, so there's no border controls at all. ObICANN: Geneva would be a swell place for a meeting. No doubt the ITU and WIPO, who are across the street from each other, would be delighted to lend meeting space. R's, John