An ARM-based laptop from Apple would make a lot of sense -- maybe to replace the MBA (the 11", especially, has a dog of a processor) -- assuming it doesn't cause too much brand confusion. A new "iBook", perhaps.

Going all ARM is implausible, especially at a time when the Intel-based Macs are still gaining marketshare in the professional world; lose the ability to virtualize Windows apps, and lose the high end performance, and suddenly all the developers I support who are bugging me for MacBook Pros rather than PC desktops/laptops will be "forget it."