I can't get enough of these types of blog posts. The app store is a fascinating study of marketing, economics and good ol' bootstrapping. Good luck in your endeavors and thanks for sharing.
Have you taken a stab at marketing? Do you have any insights in that area (either successes or failures)?
Review articles on Macworld and TUAW helped boost sales temporarily (2-3 days) but the only sustained sales were a result of having our best seller, BillMinder, featured by Apple in "What's Hot." It was great (and appreciated!) but definitely not on the level as the awesome taptaptap or tapbots. :)