I've long had a problem with the number of 'kolpac' players in English County Cricket.
Durham are playing Somerset: http://content.cricinfo.com/countycricket2009/engine/current/match/382918.html
with a grand total of four English-born players, with two who are born elsewhere but are/will be eligible for England.
Now the whole eligibility thing makes all this difficult, especially regarding Ireland.
I think 'over-seas' players should be anyone not qualified to play for England in their next game. Maybe some arrangement could be worked out so Scottish and Irish players could play as home-grown players, but not all these Kolpacs.
As an Essex supporter I have a vested interest in maybe non-Test nations not counting, so that Dutch, Danish etc. could play County Cricket thereby getting some of the exposure which should hopefully help them develop. Of course Ten Doeschate is ‘Dutch’ thereby getting out of this, but Grant Flower being Zimbabwean would count as foreign.