There is quite a lot of US visa related guesswork going on in this thread - please do seek expert advice. In my experience the application and compliance problems look much less scary when you talk to someone who does this every day. Lawyers are expensive, but try: http://teleborder.com (YC startup)

And on the global search for alternatives, should US not work out, here's some overview data of 110 most startup-friendly cities in the world: http://my.teleport.org/ -- and a mobile app for searching among them: http://teleport.org/mobile (visa data layers coming soon, too, but dozens of other cost & quality of life criteria already there)