If pads and phones are the fastest growing categories in consumer tech, surely a Padfone would be the ultimate combo? That's what ASUS thinks, and it's just introduced an Android smartphone device that comes with a tablet it can dock into. Display switching is done dynamically, so that reading emails or browsing the web on the phone portion expands itself seamlessly once it's connected into the pad. Also expanded will be battery life, with an extra cell included in the slate. The mockup ASUS is showing the world today includes a 4.3-inch smarpthone and a 10.1-inch tablet dock, but the company says it hasn't yet settled on the final dimensions of the eventual retail product.