It is 10000 i hit it playing blackjack, my character has five luck and i hit 6000 pretty easily, it took a while longer to hit 8000 and then i used the save exploit to get 10k (separate save form the one i was using so i could check to see what the limit was). So i would say there is plenty of money to be had. Basic strategy works well. Counting cards is useless because technically the deck is shuffled after every hand. It is weird but the deal stands on soft 17, can't split tens (even though you wouldn't want to), you only get one split and you can't double after splitting or double for less.
I actually never tested the room so i have no idea, he doesn't give you a time for it, he just gives you a key and says to enjoy the high roller suite.