This rumor has been heating up for a while now, but some news posted by DigiTimes this morning is reporting that the high-DPI panels will hit the MacBook Pro's, too.
They say that a "new MacBook Pro lineup" sporting 2880x1800 displays, which "sources in the upstream supply chain" should see the light of day in Q2 2012. That resolution is 400-percent more pixels than the current 13-inch MacBook Air displays, which have a resolution of just 1440x900.
Quadrupling the number of pixels is the same tactic Apple used when they put the "Retina" display into the iPhone 4 when compared to the 3GS.
If Apple do this, it might make me want to upgrade my 17-inch MacBook Pro, yes it has a nice IPS panel with a 1920x1200 resolution, but 2880x1800... oh my.