There had been some interesting claims last year that Apple had been actively testing an ARM (A5) based MacBook Air. The ARM processor is the same one that is used in the iPhone and iPad. An ARM-based MacBook Air, however, would raise a number of questions about what kind of device it might actually be. Would it run OS X, or iOS? Would it be closer to a Mac or an iOS device? One of the main advantages of using an ARM processor would be a reduction in power-requirements, but with a corresponding drop in computing power. Using ARM, however, would abandon binary compatibility with existing Mac OS X applications.

CNet reports on a research note from Citigroup analyst Richard Gardner who was able to meet with Apple CEO Tim Cook and CFO Peter Oppenheimer on Thursday. Gardner addresses this question in his note with the following:
"Tim Cook reiterated his view that rapid innovation on the iOS platform (and mobile OS platforms in general) will significantly broaden the use case for tablets, eventually pushing annual tablet volumes above those of traditional PCs. We have wondered whether Apple might offer an ARM-based version of MacBook Air at some point; we walked away from this meeting with the impression that Apple feels iPad satisfies--or will soon satisfy--the needs of those who might have been interested in such a product."
Based on his conversations with the Apple executives, it seems Gardner believes that the iPad will evolve to meet any needs that might be met with an ARM-based MacBook air.
Rumors have suggested that the iPad will likely be getting a significant upgrade in the near future, with a faster processor, improved graphics capabilities and the long rumored Retina display. Of course, Cook is unlikely to divulge specific product plans at analyst meetings, but a complete Apple transition to ARM processors seemed an unlikely prospect regardless.
Top Rated Comments
iOS = touchscreen. OS X = mouse and keyboard.
I don't know why we have these persistent debates about OS X merging with iOS, and hybrid touchscreen devices capable of running Mac software. That is Microsoft's approach, not Apple's! Apple understood that a device which tries to do everything, ends up not doing anything particularly well, and ends up adding complexity (for both developers and users) rather than reducing it. So they designed a UI specifically for a touchscreen device. I'd say they've done rather well with this approach.
You're suggesting Apple needs to copy Microsoft's approach, the one that's been failing for years to bring a user-friendly tablet to market, to ensure they do well in the market they already dominate? That doesn't make much sense to me.
Docking an iPad with a keyboard and display does not a Mac replace. This idea is more or less just another variation on the merging OS idea, to suggest that iOS will simply replace OS X. A pointer device and cursor is intimately more suited to precision work than touching a screen with your pudgy digits (which cover what you're touching). This isn't going to change in the future, unless humans evolve transparent fingers which narrow to a precision point at the end, and the ability to hold their arms extended up to a vertical screen for hours on end.
This ol' timer says no.