I think sign-profit is the one. Better check them out on google before using them. But i have heard some good opinion about them.
SIgn-Profit pays only for banners on forums signatures and not all forums only those related to Money Investment HYIP programs
It pays for sites/blogs also. All you need is to get approved by them and they approve sites from E-commerce section only. I have just found another site Adversal. Also check this one out.
The first 2 cpm ad networks listed here pay on just banner ads. They are reputable, have been around for a long time and pay some of the best rates in the industry. With the first listing I currently earn $0.50 - $0.70 cpm on each banner ad format and I use 3 different ad formats on each page where I use them on my entertainment site. I have always been paid on time by both of these networks. They also have popunders that pay around $3 - $5 CPM, but you don't have to use them. Also, these are reputable companies so you will not get popops poping up when you have only selected the banner ad. If you don't want popunders, then you will not have them. Many of the large online sites use these to monetize their site, sites with alexa rankings of even under 1,000 use them like freeonlinegames.com