Forum Moderators: skibum
Thanks.
I don't know anything about your business but I'm guessing you have around 250,000 impressions per day. As such you might be best partnering with a second level PPC. By this I mean the ones who don't actually have their own advertisers. SearchFeed.com is probably a good example.
While they will take a slice of the profits you can view them as a collective bargaining tool where a group of similarly place Webmasters are able to send traffic to the results of the bigger PPCs.
It is an interesting world you are getting into so I wish you the best of luck.