I'm willing to bet that the next major version of OS X will do away with AppKit and bring UIKit to the desktop. UIKit is already API-compatible in many ways and most of the pieces are already in place.
Robert Cringley thinks this will be a display and input device that connects to a phone: http://www.cringely.com/2013/09/19/the-secret-of-ios-7/
I think it will be a standalone device: http://anandabits.com/blog/the-secret-of-ios-7-macbook-vacuu...
The most interesting piece will be to see how Apple approaches this form factor without creating a "refrigerator toaster". I'm optimistic that we'll find out in less than a month...