The problem is not that simple. If the network alow 1 skin to offer rake back then all other skins not offering will end up loosing their players.
For exemple in RoyalCardroom network there is no one offring it and is completely prohibited by the network contract. As on oprator the only concern you have is that your player will go to a competitor site to clear the bonus but after that you get him back with a reload bonus or simply becouse your poker client is more atractive…. Most players end up with the first site they signed up in the network.
In opposite is RoyalCardClub the Prima room(the same rules aply in the Party network, it mean nothing that Party stoped it). In the network rooms are alowed to offer it. As all rooms share same players, a big player will be happy to use a rake back site. He has same oponnents just that he earn up to $5000 more per month(i talk about very big player here). As long as others offer it in the network as operator you win absolutely nothing not offering it.
I posted this to offer you a view from the eyes of an operator. Also you as affiliates should not be at all happy if poker room X from some network prohibit rake back. If someone else in the network offer it there is same risk to loose that player to a rake back site.
From my knowledge the networks not offering rake back at all and with decent traffic are PokerStars, Paradise, RoyalCardroom (and the other network sites) and Poker.com as they mentioned on other thread.