I was browsing around the developer notes for the new iBook G4, and came across a link to this article. The new iBooks use the 7457 processor! This must be how they're able to get five hours of battery life out of the suckers.
EDIT: Okay, now I'm confused. I looked a bit more at the articles on Moto's website. It says the 7457 comes with 512k of L2 cache built-in. Would Apple cripple the L2 cache? Then I looked at the specs for the 7455 - it comes with 256k L2 and operates at all the speeds that the iBooks do. So either Apple crippled the cache to differentiate from the PowerBooks, or they're lying as to what processor they're using.
EDIT: Okay, now I'm confused. I looked a bit more at the articles on Moto's website. It says the 7457 comes with 512k of L2 cache built-in. Would Apple cripple the L2 cache? Then I looked at the specs for the 7455 - it comes with 256k L2 and operates at all the speeds that the iBooks do. So either Apple crippled the cache to differentiate from the PowerBooks, or they're lying as to what processor they're using.