Bellagio spreads the highest regularly running all limit game in vegas, 80/160. Word of mouth, they are able to spread a few tables of it, like 2-3 I think on weekends, and during tournaments or basically any time people are interested, they will spread a higher game (bk playing 150/300 is an example).

Mirage spreads a 40/80, and I don't think anyone else has had success getting a big limit game going.

As for the composition of players or how it compares to online... For that I have no idea.