That would be nice, definitely, but as far as I know, the only people with that sort of power are the Avatar and this Amon person, and we've got no idea where he figured out how to do it. He says he was a non-bender who was given his ability by the spirits, which... well, we don't know anything about the man other than what he says about himself. Perhaps he's being truthful.

And, well, if he isn't, he's not about to tell the method to anyone who wants to restore people's bending, given that it's his mission to purge bending from the world.