Easy solution. Win your patent case, collect. Lose, pay 10 times + legal fees.
A little company I worked for in Vermont got one of these troll messages because we had a office printer/scanner/etc.
They were really afraid of the legalese attached to the "pay up or be sued" email. I let them know that it wasn't real - altho this is the same troll in this piece - and to just ignore the email.
However, there are some who will bow to the fear of being sued or having their name besmirched (God, how I love that word). And all of these companies expend quite a bit of resources figuring out how to react.
The trolls should be made to pay when they are in the wrong. And pay significantly.