I think alternative donations would be better.
Very soon people will be selling PACC for Tibianic money, so that's hardly different than donating 3,5euro for 10-20k gold. Yes, they would be able to buy unlimited money, but that would favor the server, and it wouldn't be that overpowered, really.
Absolutely no one will play an OT with Facc and if they don't want to donate or farm extra money every month - they simply won't play here = small playerbase.