Dell XPS 11: wrong screen dpi, GUI elements are too small

[Sergey]

Release: Linux Mint 16 "petra"
Edition: MATE 64-bit

Dell XPS 11 comes with a small 11.6" high-resolution, high-dpi screen.
Although xrandr does report correct number of pixels as well as correct physical dimensions, X11 reports 96 dpi resulting in microscopic, almost unusable GUI elements:

$ xrandr | egrep 'Screen|mm'
Screen 0: minimum 320 x 200, current 2560 x 1440, maximum 32767 x 32767
eDP1 connected 2560x1440+0+0 (normal left inverted right x axis y axis) 257mm x 145mm

$ xdpyinfo | grep -A2 ^screen
screen #0:
  dimensions: 2560x1440 pixels (677x381 millimeters)
  resolution: 96x96 dots per inch

Manually setting "DispaySize" does fix the dpi in X11, but has no effect on the size of GUI elements:

/etc/X11/xorg.conf.d/10-monitor.conf:
--------------------------------------------
Section "Monitor"
    Identifier "<default monitor>"
    DisplaySize 257 145 # In millimeters
EndSection
--------------------------------------------

$ xdpyinfo | grep -A2 ^screen
screen #0:
  dimensions: 2560x1440 pixels (257x145 millimeters)
  resolution: 253x252 dots per inch

Increasing Font DPI in "Control Center -> Appearance -> Fonts -> Details -> Resolition" does make the UI more usable, but produces suboptimal results as many UI elements do not scale properly with the font size (icons in the menus, window decorations, labels under shortcuts on the desktop, hardcoded sizes of some windows/dialogs, etc). In addition, further application-specific tweaking (custom font sizes, scale/zoom factors, etc) is required to make other popular software (such as firefox and chromium for example) more usable.

Expected behaviour:
Default installation should properly detect screen geometry (physical dimensions, dpi, etc) and properly scale *all* UI elements. The same default behaviour should apply to all software supported and provided via default mint repositories.