Hi
I built a cross-platform editor for plist files in C++/Qt
Its called “Plistinator” and it handles binary and XML, and runs on Mac, Windows and Linux.
I built it while working on my Cocos2D game “Ethex 2080” http://plistinator.com/plistinator-story.html
Lots of folks here who need to edit plist files will find it useful I think.