Apple's yearly developer conference should see iOS 8, OS X 10.10, and likely some hardware.
OS X 10.7.3 Beta Reveals Active Work on 'Retina' Display Support for Mac
With new claims that Apple is set to release a new 15" MacBook Pro offering a resolution of 2880x1800 early next year, Apple's work on its HiDPI software support has also been gaining renewed attention. By doubling the resolution in each dimension over the existing 1440x900 MacBook Pro, Apple would achieve four times the number of pixels and provide developers with an easy way to scale existing artwork.
Evidence of Apple's continued work on HiDPI has shown up in developer builds of OS X 10.7.3, with the "Get Info" window for applications seeing the addition of an "Open in HIDPI mode" checkbox. But while that checkbox would presumably automatically use higher-resolution fonts and graphics that would display at the same absolute size as existing elements, it has not been functional in developer builds where it is present.
With yesterday's release of Build 11D36 to developers, Apple has now removed that checkbox from the "Get Info" window entirely. While its removal may suggest a step backward in Apple's implementation of HiDPI support, it is routine for Apple to activate and deactivate portions of features as it works on them. Consequently, the mere change in the checkbox's visibility in the new build indicates that Apple is indeed likely actively working on the feature.