With the revision 22806 it is possible to shade a window, but impossible to unshade a window with the keyboard shortcut.
Actually it's worse than that. No keyboard shortcut work on shaded windows.
This is because the client app is unmapped (See bug #2168). The wy to fix that would be to grab the keyys on the root and not an every client window. That would save a *lot* of grabs and, incidently, also fix that bug.
Should be fixed with rev. 23120
It works :)