A friend of mine used to encode his file sharing with false IP's to hide his ID for music and movie downloads. He is a senior Java expert and said he had a program that generates random IPs for each download. Apparently, he could do it for uploads as well. I checked out Google and there are many citations for such a thing. All I know, he never was caught sharing.
More often than not, when someone comes up with a method of doing something, s/he could also come up with a methhod of undooing it. Maybe your friend could help.