They would have announced it today if that was the case. Currently there isn't a display transport capable of pushing that many pixels. DispayPort 1.2 can't do it on a single port and that's what Apple has MacBooks and Mac Pro.
Yes, and that's already being used by the first batch of 4K monitors and is called MST. This models the monitor as 2 lower-resolution displays and drives them with two separate signals.
It has a lot of compatibility problems, and is hacky as hell. I doubt Apple would adopt this as an official/first-class solution to anything.
Solving "compatibility problems" is what Apple do best by requiring you have an Apple Mac Pro and an Apple Cinema Display and not supporting any other configuration
