The new Macbook Pro Retina has two Thunderbolt ports. In theory, they could build a display using both, each driving half of the screen. Although it's unlikely to happen.
Would that not be pretty similar to dual-link DVI? Though I believe that was part of the DVI specification whereas I've never heard the current Thunderbolt standards to have provision for such. Regardless, I wouldn't be shocked for Apple to do it at least initially in their own non-standard way.
