A different idea could be to make a compelete new coin and everybody gets one. The number of coins is fixed with exactly the number of people on the earth when it is created. For showing your passport everybody can claim exactly 1 coin. So every coin would be given away for free and then they can be traded on the the big exchanges. It is hard to imagine what would happen, but I would expect that many people would instantly sell their coin for some free money. So the initial price would be very low. But once the initial coins are sold I would expect the price to rise.