Banner Ad Network (Like Adsense, Clicksor, Adbrite etc)

Hi, I need to create a banner ad network, basically the publisher generates a code and puts on his webpage, and advertisers create campaigns and bid on CPM basis, so the advertisers that bid more have their ads shown. The ad network will allow category segmentation, and some other simple targeting features, also it will allow conversion tracking and all metrics calculation (revenue, profit, cpm, ecpc, etc) Ability to each publisher add multiple sites but each one of them must go through review A very very complete admin panel with almost all possible administration options and all configurable to have multiple user levels I prefer someone that has experience with ad networks and has used some. I can provide you with some examples of similar ad networks Must be done using some PHP framework (zend, symfony etc) You also need to take care of the layout or find a designer to do it.