Treasure Island still has a good 6 deck $10 3:2 game, it is the only place on the strip I'll play anymore. You have to go to the tables just inside the entrance where the Sirens show used to be, walk straight inside and then the pit on the right across from the cashier and high roller area. Just be careful because they do have 6:5 games mixed in there. The pit near the bar by the front entrance also has some $10 3:2 games. I gravitate for TI almost exclusively for gaming because of that, even though the rest of the hotel doesn't do much for me.
Mirage, MGM and Mandalay Bay all had $10 3:2 games not long ago, but last time I was there I couldn't find one at any. Mirage in particular went full 6:5 and took away most of their tables. The best bet for a legit game will always be downtown, but on the strip your only consistent option is TI at this point.