Do you need seperate sheets per country or could you condense the view down and perhaps use section access to limit the users countries they can see?
Or if they have to be seperate perhaps have separate apps for each country just to reduce the number of sheets the user is faced with and make it more managable.
Finaly look at what the users are using the app for. Are they consumers or analysts? Perhaps they could be satifised with static country reports that could be generated from your app and distributed out to the users via nPrinting.