Hey I got your PM... sorry so slow to get back to you. I'm moving 2000 miles next week, and things are getting hectic. Lol...
About your question... Theoretically, it could be done. It would involve cutting all the traces to both sticks and reversing the connections by soldering wires in place. HOWEVER, this would be extremely hard to accomplish without damaging the controller in some way.
Once I get settled in Phoenix, there are some new controller projects I plan on tackling (Xbox 360 wireless, Gamecube). I'll take a harder look at your question then, maybe I can come up with a solution!