ABC News (Joanna!):
While the design of the laptop might be similar (though thinner), the part of the laptop you spend the most time looking at is getting a major overhaul — the screen. The laptop will see the introduction of the “Mac Retina Display,” which is said to have a very high resolution. ABC News has similarly heard from its own sources that both the next MacBook Pro and the iMac would be getting very, very high resolution displays. Apple refreshed its new iPad with a Retina Display in March.
The 21.5-inch iMac would see a pixel count in the range of the 17-inch MacBook Pro as its 1920x1080 resolution would be bumped to 3840x2160, but the 27-inch iMac would move from its current resolution of 2560x1440 to a monster Retina display at 5120x2880. The same panel could also be used in a revised Apple Thunderbolt Display should hardware be able to support the resolution.
It Won't be 5120x2880 but 4K (4096x2304) would be nice. Heck, 3849x2169 will get me hot and bothered.