Ah that's pretty interesting stuff. When Mac OS X was first out I remember one of its 'features' was that it was designed with higher-res monitors in mind. e.g The Menu bar was thicker than OS 9's and you could scale up icon sizes so that they wouldn't be too small on huge displays. The menu bar thickness still annoys me to this day, it's far far too big on a 1024x768 display and I often run out of room for menus!
Would this feature allow me to 'shrink' various objects like the menu bar and window borders? Or is it designed to be automatic so that the whole UI adjusts when you change resolution? On newer monitors I can definitely see this being useful. I've yet to see what the UI looks like on a 30" Apple display, but it's starting to get abit too 'small' even on the 20".