MacOS Rumors recaps some of the recent rumors and also suggests that the upcoming G5 may be based on IBM hardware:
Apple sources have recently told Rumors that when Apple ships computers branded as PowerMac G5s next year, they will almost certainly not include Motorola PowerPC 8500 processors, which are the G5 as we know it today -- they will be IBM-built chips based on its Power4 architecture, and may even include multiple cores on a single chip.
