The map

Whether this idea of large regions is good or not I don't know, but on a much smaller level we have it already in many border regions of Germany: Cross national bodies composed of the local regions from both sides (or even three sides (where three countries meet) discuss and (when there is agreement even suggest) such threatening things like a harmonisation of the time tables of local public transport, taking into account public holidays of the neighbours in opening times, including police and fire brigade of the other country in a local alarm plan in case of a big disaster (explosion in a chemical plant, for instance).

In the old times the information had to go up to the German minister responsible for this and only he could inform the respective say French minister and from him the information would go down to the locals. Days later they would know what kind of contamination was crossing the border after an explosion.

It even has happened as a consequence of these trans-national bodies that the nearest fire brigade of the other country has crossed the border to help without waiting for the consent of the ministers of interior affairs after consultation with the ministers of defense of both sides. At the Dutch-German border, even both police forces (in hot pursuit only) may cross the border and make arrests in the near border region of the other country.

Wolfgang (not feeling that German sovereignty suffers from these agreed upon exceptions)