I just came back from vacation and I see a wonderful post giving idea of organizing a Windows HD worlcup !
I totally support your ideas !
You can add me in the french team

Concerning the numbers of teams, why not creating teams simply defined by a static amount of players per pool.
An example:
We define 6 players per team:
If there are 24 french players, there will be 4 french teams.
And we do the same for all the same for all the other countries.
it would avoid that some good players would be disqualified too quickly.
Just an idea...