The top-by-country pageviews API doesn't allow any querying of the data for a particular country. Instead, the only way to get broader data about a country is by using hundreds or thousands of requests for data on all countries, and pulling out the bits of relevant data. The Pageviews API should allow specifying a country, much like it allows specifying an access method.

(Ideally, there would be a way to request for multiple/all particular projects at once, but that's not even available for regular non-country-specific requests yet... Wikistats could make some interesting charts with that data.)

I suspect there would be more use for finding the progression and project-distribution of readers in a single country, than there would be for finding the geographic distribution of projects at a single point in time.

(Are there currently dumps for the pageviews data, as another possible alternative to loads of API requests? I haven't been able to find one.)