Does anyone know how expensive the Li-Polymer batteries are? The iPod uses one, and I know that a lot of development dollars are going into battery technology... that would be a great addition to the notebook lines if battery life was increased due to the newer materials used. I understand that li-poly batteries are also more convenient to shape and produce. And another battery I've heard a little about is a nickel-zinc variety. I don't suppose there are any battery gurus in here?