I just found this thread. I started reading at page one and read all the way through to page 18! I subscribe to the Crossfit Journal and I've watched several of XRe's videos from Crossfit.
USPSA is a unique shooting discipline that combines many things, speed, accuracy, stage tactics, different shooting positions and a certain level of fitness. If you "specialize" in shooting while standing still or just two handed shooting, you won't do well at stages that require shooting while moving or one handed shooting. At a match you need to be able to perform on demand, consistently, at everything.
Crossfit's specialty is not specializing and they basically train for everything. The workouts constantly change and USPSA stages constantly change. I see correlation between Crossfit and USPSA in the fact that the challenges constantly change and you must be good at everything to succeed. They are perfect for each other!