Sorry, I have no advice, but I love this idea, I've been looking for an automated system to incorporate text ads. I just stumbled upon martketbanker.com, it looks like a pretty good solution, but they want 25% of all revenue... I'd rather find an in-house solution that can be catered and controlled by me. I'm no programer, but I'd love to see something like this come out as a plug in. Good Luck with your project!