I realize that this post is three years old and that i probably won't receive a reply; however, I am quite passionate about the realness, use, and application of the short distance punching in the manner that Bruce Lee pioneered.
I have always cringed at the nay-sayers regarding the 'one-inch punch'. It is in fact very real, and it is much more than a 'push'. Yes, it came from Gung-Fu originally, just as everything Bruce did came from some form or style. That is the point and meaning of Jeet Kune Do; to take whatever you can from any style and make it your own. Bruce himself said "reject "forms" take what is useful to you; discard the rest". Did he learn a variation of this technique while studying Gung-Fu? Yes; However, what was unique was the twist he put on it. He modified it, as he did with everything else, to make it his own and therefore better (for him at least). It does have pracital application as well. Imagine the possibilties of being able to hit an attacker with your full force from little to no distance! That holds too many possibilities to even discuss. Finally, here is some physical evidence against those who say that it is merely a push:http://www.youtube.com/watch?v=Kx9iPFMriz0
This is a link to a poorly made but poignant documentary regarding the one inch punch. I put it here simply for the demonstration of the ability to break boards unsing a short-distnaced punch. Clearly not a push!