Photos of the new motherboard leaked a few months ago. Seem now to be real.
http://www.joystiq.com/2010/03/17/ru...images-leaked/
Main changes are the size, one fan instead of two as the CPU and GPU are now intergrated.
5 usb ports, the optical port on the console and large internal HDD.
Its no more powerful than the current console though Madgamer, they wouldn't do that.