I am looking for CPM also popup/popunder networks which have referral/2-tier/multi-tier program. I know about few who pays and some dont accept my site even I want just refer webmasters like casalemedia or valueclick(let me know if you know how to get in just to refer).
Webmoney, here are some CPM popup programs. Some of them also have popunders, cpm banners, etc. You can also easily see which ones are 1 tier, 2 tier, etc. Hope that helps.
I know your site very well John unfortunately I didnt have luck to get into 1st 2... than popupad.net looks like is just quit since I didnt get payment after 3 months (before I got payments) and RealtechNetwork has terrible referral program I dont even see how many referrals I have. So there are only 2 left for me which are good (adversal and paypopup) and that is not much. If there is someone who knows how to get into valueclick and casalemedia just to refer let me know. I tryed to write them but they always say the same... It looks like they dont want their links to referral program o my sites which are related as you can see.