The limits are dynamically adjusted based on house funds, so at the time the limit was 50 but now it is 5, at least thats from my understanding.
I think this is dangerous for the house, because the limit dynamically reduces immediately after any large payout.
Therefore, most of the largest bets are going to be ones that the house loses.
The tradeoff ribuck is that there is supposed to be guaranteed funds to payout any win, granted there have been problems with unconfirmed funds being used to payout wins, but they come through eventually.
If there was no dynamic limit and two big payoffs hit in close proximity then SatoshiDICE may be put in the position of having to say "Umm... we will have your money tomorrow" which would kill it's rep.
My previous 2 that I posted got paid shortly after posting have to really wonder if it the power of the forums ?
I still have a few outstanding though ..