Joanna Stern of ABC News has reported that not only will MacBook Pros have Retina Display but the high-resolution screen will also come to the iMac.
Following in the footsteps of the iPhone 4 / 4S and now the new iPad, The Retina Display could land on the entire range of Apple computers to become the standard of the company and thus make use of the HiDPI interface that they are introducing in their operating system.
If the 15-inch MacBook Pro could achieve 2880x1800 resolution, the 21,5-inch iMac would go up to 3840x2160.
For the 27-inch iMac, the resolution could be increased from 2560 × 1440 to about monstrous 5120 × 2880 pixels, twice the resolution it currently has. In addition, this same panel could be used in a new Apple Thunderbolt Display to make the jump to the Retina Display.
More information - Apple could launch a MacBook Pro with Retina Display
Source - MacRumors