Powell is not going to satisfy the Bush base IMHO. I do not think he is pro-life and he let's his underlings mouth off about how peeved he is about this or that Bush policy. He needs to be gone in a second term, and I bet he wants to be gone. I think Condi is pro-life, but I am not sure. Any VP is probably going to need to be pro-life.
Powell would not take the job anyway, so this is all purely nonsense speculation. As you say, he is out if the president gets a second term.