My suggestion for colours would be white/black pips all round, and the solid colours for the provinces;
Red
Yellow
Blue
Green
White
That way, people could mix these colours to get the province they wanted. For example, as a Talabecland fan, I could get the red and yellow. Simple. Reikland, get the red and white. etc....
As for organizing this privately, any volunteers? I am sure there would be interest.