I earlier posted an article describing the new dual core G4 class e600 chip from Freescale. Freescale has now added some details in a press release. Some of the details are listed below:
e600 MPC8641D Dual Core (Pin-compatible single core version also available)
Two 1 MB L2 caches
Dual AltiVec units
15-25 Watts typical
Integrated memory bus, up to 667 MHz
1 Gbps Ethernet
This MPC8641D brings the possibility of a dual core PowerBook with reasonable power characteristics, although one wonders if Apple will choose to use a single core chip, either a G5 970FX derivative or else a single core variant of the MPC8641D.
In addition, Freescale will release the G4 MPC7448, which is pin-for-pin compatible with the MPC7447A, but which includes double the L2 cache. The MPC7448 is also based off the e600 core, but does not include an integrated memory controller.
The MPC7448 would be the logical chip upgrade for the iBook. It's also possible that Apple would use this chip in the next iteration of the PowerBook before it goes to a new architecture.