As Tuaw pointed out Mac OS X Lion might support 3200 x 2000 pixels screens (it’s still far away from iphone4’s retina display pixel density), but what is technical possibilities of it?
So far, the only interface which could support such resolution is DisplayPort 1.2, which maximum is 3840 х 2400 @ 60 hz.
The only video cards to support DP1,2 is AMD’s Cayman (69×0), Barts (68×0, 6790), Turks (6570/6670) and Caicos (6450).
None of them officialy supports more the 2560×1600 tho, but maybe amd can write special drivers for apple, who knows..
Also, I doubt that Turks or Caicos can works well with 3d stuff at 3200×2000 resolution, they are just too weak for it.
Cayman is too hot and power hungry for macs (imacs probably this time ?). So, maybe it will be Barts. We will not see new AMD/NVIDIA cards until Q3/Q4 anyway.