I'm also eagerly awaiting HiDPI support (I have one of those QHD screens on a 15" display, 3200x1800!). There is apparently some support for it in the GNOME version (I've read it was not perfect though). Don't recall where I read this but it was rumored HiDPI may come to 14.10. Probably no more than a rumor... But at least a version number to look at helps me cope :)