Comment 3 for bug 1082237

mpt, GNOME Shell 3.6 has a cool feature.
In System Settings>Universal Access, turn Zoom on.
Click Options to open Zoom Options.
Switch to the Color Effects tab and turn Color down to None.
Now even apps which don't ship a High Contrast icon are at least grayscale.

I think adding a HighContrast icon should be something we should add to app development checklists, similar to how shipping a 128x128 icon (or even 256x256) should already be there but is a relatively recent change. Anyway, there are lots of small details that we care about for the main CD that we currently don't block from being in the Ubuntu archives.