It's not just the Mac, either. I'm willing to bet that it's coming to the Apple TV, too.
Apps would make Steve Jobs' hobby much more appealing, and it would mean that all of Apple's consumer products - iPod, iPhone, iMac, iPad and Apple TV - would share the same interface, the same apps and the same data.
That data will be stored centrally, either via the cloud or on a shared network storage device such as a Time Capsule. Remember Apple's enormous, billion-dollar data centre? That's for the cloud bit.
Don't believe me? Ask the developers. When Ars Technica put together a panel of Apple devs, they were unanimous: Mac OS X will eventually be subsumed by iOS. "Developers are seeing iOS influencing Mac OS X instead of the other way around", Chris Foresman reports.
Cabel Sasser from Panic's prediction rings true: "I could see a gradual, slow merger between iOS and Mac OS X styles and approaches," he says. "It doesn't make sense for them to be developing two of everything, one good, one not as good - two calendars, two address books. It's got to merge somehow."
This isn't going to happen overnight, but it's going to happen. The reason it's going to happen is that for very many things, iOS is better than OS X, let alone Windows or desktop Linux.
Unlike traditional operating systems, iOS is immediate. Every iPhone or iPad owner with young children has watched their kids pick up the device, launch a few apps, delete all of Daddy's data and run up enormous credit card bills: there's no learning curve whatsoever, no time spent learning the operating system before you can actually do something. It's an operating system that gets out of the way.
You might call it "computing for the rest of us".
The vision is this: iPods, iPhones, iPads and Apple TV for everyday stuff; iMacs for editing and other tasks that need proper horsepower; Mac Pros for content creation.
Steve Jobs recently spoke about cars and trucks. In the near future, i-devices and Apple TV are the cars, and Mac Pros are the trucks.
By bringing out the Magic Trackpad, Apple has given the mouse its marching orders: don't be entirely surprised if there's a Magic Trackpad Pro to offer pen-based input for artists and anyone else who'll miss the precision of mouse input.
But for the rest of us, Apple clearly thinks fat-fingered fun is the future. I think it's right.