I’ve been wondering about this topic lately myself. It seems that a few sites are being marketed under “rakeback” schemes, though I wonder if the affiliate programs themselves are aware of it. Took a guess and typed in http://www.rakeback.com and this site is offering rakeback deals for 7 sultans, royal vegas, and party poker.
Does Party Poker even allow this? And, if they do, how would you even track the activity of a player with their stats? The only way you could do it is to either set up a unique tracker for each Party Poker player you refer, or have the player send screenshots of their account to verify their play. Either seems fraught with challenges.