How about Google Adsense Premium account?

Google AdSense, which has the largest number of publishers in its network also has a rarely know feature called ‘Premium Google AdSense Account’. This feature is particularly for those sites which receive more than 20 million page views or 5 million searches a month.

Some of the sites like CNN, About.com, MySpace, AOL are among Premium AdSense Account Holders. The left image is the screenshot of the AdSense’s ads on EzineArticles.com.
As you can see at the left, these ads are not like normal AdSense’s ads. Premium AdSense Ads can be customized to fit the site’s design and layout. This is an advantage of Premium AdSense Account.

Apart from this, Premium AdSense Account Holders have some exceptions in AdSense TOS. Some of them are :
Unlike normal publishers, premium publishers can pre-populate the search box and link them directly to AdSense Search Result Pages.

Premium AdSense Publishers can also place mature content on their site. They are even allowed to publish content about Gambling and Casino.

Premium AdSense Account Holders can also remove the ‘Ads By Google’ line and place something of their own. Thus, the visitors will not know that these ads are served by Google.
Google provides a special Account manager through which the AdSense publishers can customize the colors, layout, fonts etc.. and change the way the ads look.

Premium Publishers can negotiate the percentage shared between them and Google while normal publishers have to accept whatever Google gives.

Finally, Google AdSense Premium Publishers get an opportunity to become much more richer.

Via: http://www.websack.net/2008/09/24/learn-about-premium-adsense-account/