I'm already drooling over the idea of PC makers like Apple finally starting to push for truly high-resolution displays. If you look back the top-of-the-line CRT displays of yore, it's almost crazy my 24" 1920×1080 is considered high-resolution. There have been rumblings of high DPI displays for years now, both in terms of software as in terms of hardware.
And now we have DigiTimes (not an entirely accurate source, but alas), claiming Apple is going to introduce 2880×1800 displays on their MacBook Pro line in the second quarter of next year. Whether or not this is a plausible rumour depends on two things: hardware and software.
Hardware-wise, we're probably ready. Display makers like Samsung and LG have been demonstrating high DPI panels for years now, and they're bound to end up at production quality at some point. Whether pricing will be anywhere near acceptable remains to be seen - but considering Apple is supposedly mulling this display option for its Pro line, it's safe to assume it's going to be a very expensive BTO option.The bigger issue is software. Mac OS X 10.7 Lion has support for something called HiDPI resolution modes, something you have to enable via the Quartz Debug application. The basic gist of HiDPI is the same as what the iPhone 4 did for iOS; instead of using vector graphics to realise true resolution independence, you just create higher-resolution versions of all graphical elements in the operating system. Graphics that have not been updated are drawn with four pixels for each single pixel.
As it currently stands in Lion, these HiDPI modes are not yet ready, with lots of graphical elements not yet being drawn in high resolution. In other words, if Apple is truly planning on shipping these displays, it's going to need to release a pretty hefty update to Lion first. And then the waiting starts: third party applications need to be updated as well.
Windows also has support for high DPI displays, but I'm not sure just how advanced it is. I use a higher DPI setting on the Windows 7 box attached to my TV to make the few cases where I drop out of Boxee more bearable, but perfect it is not. Windows has supported making applications high DPI aware for a very long time, and during the development of Windows 7, Microsoft's data showed that most applications (91%) have no issues running at higher DPIs - I'm not sure how good it is now.
All in all, with the competition knocking on Apple's door with regards to laptops (except for the trackpad, my Asus Zenbook is just as good as the MacBook Air it replaces, with the bonus of not having to use Mac OS X), this could be Apple's way of widening the gap again. In addition, even if it's just an expensive BTO option, this would finally broaden the availability of high DPI displays.