That is a very good question, and it's one that comes up in the U.S. context as well.
There are several elements in play here. One is the notion of autonomy, and giving some geographic space an autonomous system of government. We see things that more or less are like that with various first nation arrangements in North America.
The other element in this proposal, though, is the purely economic imperative of urbanization as the path to opportunity. Almost everything people do is more productive in a dense urban area. The only exceptions are things like farming or mineral extraction, which require lots of land.
The key here is not just to provide conditions of trust and opportunity and employment, but also all the benefits that come from a dense urban productive environment and living environment.
This zone in Honduras will be open to migration from all of Central America and Latin America—even all of the world. For example before 2008, a million people a year left Central America and Latin America to come to the United States. At a flow of a million people a year, this zone could get to the size of a city of 10 million people within about 10 years.
The difference in the legal environment in Canada, I'm sure, and the United States is that no one right now is willing to contemplate letting millions of people who want to move into cities come as landed immigrants or permanent residents in our countries. For a variety of reasons, we're not ready to contemplate that kind of inflow.
You could create a special autonomous region in Canada or the United States, but it wouldn't have a viable chance to become a city of 10 million people that is a global hub that can compete for the best talent of the future.