Why not? Players don't care which bankroll they're playing against so long as they can make the bets they want to make.
One problem I can see with it is that the server seed is going to be different for the two bankrolls isn't it?
You're going to have to present the player with two different seed hashes, one for if they bet to win over a threshold and the other for under it. Gamblers can be a suspicious lot, and having two different seeds, one for big bets and one for small could turn them off.
You answered the why not in your second response, 2 different seeds which makes it not ideal. RHavar agreed to hold off though on this so it is currently a non issue. As you probably can tell I was not fighting for casino income but rather inclusion of small bankroll players who only have satoshi's to bet.