MacMagazine.com.br has posted an interesting find. Apparently the latest build of Lion includes some icons which are sized at 1024x1024. That's twice the current 512x512 size of icons in Snow Leopard (four times the pixel count, but 2x larger in each dimension). Additionally, on April 2nd, Mac blog OSXDaily found some of the default wallpaper resolutions in Lion to be as large as 3200×2000 pixels.
These wallpaper and icon size increases are interesting because, as far as the wallpaper resolution goes, Apple currently does not make a display that supports that high of a pixel density. Given the fact that Apple is bumping up its icon and wallpaper sizes, it could point to a future where Macs sport high-density Retina displays.
Indeed, MacRumors points out that Apple has built in support for HiDPI display modes in Lion. "These HiDPI modes allow developers to supply 2x-enlarged images to support double-high resolution displays," according to MacRumors. "Like the iPhone 4's Retina Display, this means that user interface elements will remain the same size, but everything will be twice the resolution and, therefore, twice as detailed."