Absolute undeniable evidence for existence of God?

[CapnAwesome]

Any evidence that can be peer-reviewed and reproduced is good enough.

Imagine the evidence required to show that Bigfoot exists. Pictures aren't enough to show that he is real: we need to be in constant contact with the creature, be able to meet up with it from time to time, or even capture it, file away a blood sample...anything more than the silly plaster casts of its foot that we currently have.

Exactly! It's not like it would be very hard to prove that a creature like that exists. All you have to do is have it appear. It's the same with God. If God appeared that would be good enough for me. The only objection that I've really heard to this is that it might be an extra-terrestrial that is so technologically advanced as to be indistinguishable from God. Well in that case it doesn't really matter. If there was an animal that was not Bigfoot but indistinguishable from Bigfoot would people say that Bigfoot doesn't exist still?

Of course the existence of God fails this very easy test. Why not appear? It doesn't subvert free-will like Theists will often claim. You'd still be free to believe or not believe or worship or not worship. So in short the evidence I would accept would be very easy to produce and yet it doesn't happen.