I don't know if this came across in my blog post: cold calling is not in the cards here. I think there is a market niche which exists where it is not profitable to do the cold calling, and believe that I can reach it with scalable approaches like AdWords and AdSense, in much the same way that I reached individual teachers because doing enterprise sales to their school districts would not have been possible.
Just looking at it, my instinct is saying "nah", so if I can retrain and learn some new stuff that would be very useful.
I think direct marketing (postcards, ads in trade journals, banner ads on trade portal websites) will work better than Adwords for this.
Because I think that your solution is something that a lot of businesses need and can get a benefit from. But its not a solution that all of these businesses search for.
So you will do better with a more pro-active marketing tactic. Take the educational approach - get case studies written about your first few clients - in their trade journals. Such a PR / case study approach will work better for you than Adwords.