I don't want to go back to school now, I am tired of that. How about working for a US company outside of the USA, before to move within the company ?
Try to spend 1 or 2 years in Europe working for a big institution and also start a submitting code to big, shinny open source projects in the area that is of your interest. Then you can build a portfolio. Also be active here, on github and on SO, will help considerably from what I've seen.