Brian Balsbaugh is the man with the info. He's an agent for a lot of top players and is obviously a much busier man than he was five years ago. Here's a list of the people he looks after:
http://pokerroyalty.com/player-management.php
He's the sane man's Oliver Tse......
But I think the most interesting part of this discussion is a player's motivation to make all these endorsement deals. I mean, with the boom of coaching sites and the games getting a lot tougher for celebrity pros, they need to endorse all these products to make a living whereas they could just sit in a game and win money.
A high stakes player could previously work whatever hours he wanted at the Bellagio and make a living from that, but since there aren't many players who are consistently +EV in the biggest games now they have to do all this other stuff.