Your best option at this point is going to be getting there early and buying them on site. I know that's a drive, but in any event, you'd almost definitely have to meet the seller tomorrow anyway, which poses its own risk.
But I've been looking for a few extras all week, and neither the ticket office or any of my usual contacts have any. Demand will be high, and you won't be paying face, but there will be some available, and you may get lucky and get a good price from someone who just wants to sell them and get it out of the way.