If you're Canadian and have a Mastermind toy store nearby, you might want to check them out. The one near me still has several boxes of Series II minifigures for sale, and discussion with the staff suggests that this might be true for other stores as well. It seems like they have a backlog of them still in inventory.
I was able to pick up three more Spartans as well as a disco dancer; they had a buy three get one free deal, and I wanted the disco dancer's hair. If you want to pick up some of the older figures at MSRP and not Bricklink prices, you should check them out. They also have a solid inventory of Series IV and Series V, although, admittedly, neither of those are difficult to find.