The Chinese website Unika.com have what they claim are the Spec's for Nintendo's next-gen Revolution! Here's a quick translation by Google.

CPU: IBM G5 Custom x 4 2.5GHz cores, level 1 cache 128KB, a level 2 cache 512KB share

GPU: RN520 x 2core 16MB eDRAM, PC R520 AMR technology supports 720p and 1080i.

Unika.com