I'm not completely positive, but I believe the Wacom mice may be kinetically powered to transmit a very faint electromagnetic signal to the tablet. The tablet must be made out of a material sensitive to that kind of signal. I know that the mouse does not work off the tablet, so technically, if apple wanted to implement that kind of technology, both the mouse and the keyboard would have to be placed on some sort of large wired tablet... which probably aint gonna happen.
Well, just FYI, the mouse on this computer is an optical 3-button Mouse Systems mouse, but it's an old type of optical mouse. It requires a special reflective mousepad to work. It's still corded, but it's the same idea. However, I doubt Apple would do this because it would tether the user to the computer still, effectively defeating the purpose of a cordless mouse.
The Wacom Mice work almost identically to the tablet pens themselves. It's all to do with some sort of material which conducts electricity, and so slight charges can bounce up and back down the tablet to register its location. The mice, to the best of my knowledge have about four contact points, to facilitate the mice buttons and the motion of the mouse.
Hmmm... The German info and the "leaked" info seem to conflict - I have a hard time believing that Apple would call it BOTH "G5" in sales material, and "PowerMacintosh 970" on the product itself. Which to believe (if either one?)??
...I'm going to go with the "G5", personally. This rumor sounds like so much fluff...