I were once thinking about the nations-cup too. I had an idea, that some countries with lesser players, 1-3 could have permission to link up with one other small country. Fin-Swe for example. A 3vs3 should fit that form quite well possibly. Then the rest could be somewhat;

Germany-Slovenia
Israel-Bulg?
And then I guess the rest could play with their very own? Possibly?
Britain, Netherlands, Belgium, USA, Canada, Poland...Some other?