I would abandon the US market until I had the funding to fight trolls or they get responsible legislation going. Once foreign corp. X have got the funding I don't know what would stop a mysterious new US corp. Z from buying access to the X userbase and APIs with the express purpose of doing the exact same thing as X but domestically. And then, once the patent business has been cleared up, merge them. It might have to be as convoluted as X -> unsullied foreign corp. Y -> Z to launder the relationship but I bet it's possible.