coan.net: I think that is a GREAT idea! That is probably the best way to control the amount of chips in play. Something visual in the poker room is definitely a good idea, maybe make certain items upgradable, such as a prize cup, you can get the next biggest one once you get to a certain chip count. The only thing that might get in the way is that we don't want to add to many things to the poker interface that don't have anything to do with the game and would crowd the screen.
Another thing that Fencer could maybe consider is allowing the exchange of chips for brains. You could cash at a certain exchange rate of chips to brains. That might be kind of getting too close to playing for real money, but since you can't actually get cash for brains it might be OK.