How about a crowd sourcing website for patent invalidation. Make it proactive. You get sued or threatened. You go online and post the patent. Maybe other people in the same situation, including once who have yet to be sued, can pitch in. There is one thing that most patent trolls are terrified of, and it's a well researched and filed invalidation claim.

My other suggestion, if you think you might get sued for a particular aspect of your app, try to isolate it as much as possible. For instance, if you have an app that makes money through ads. Form one company that makes the app and another that pays a nominal fee to display ads in that app. One Company makes the money, the other "infringes."

Finally, get any lawyer, any one that will agree to represent you and file a declarative action in your jurisdiction to invalidate your claim.

Just my 2 cents. Maybe some real patent lawyers can chime in.