Dash to Dock: Reveal on <Win> key

Actually, this is less of a question for Ubuntu than for Gnome itself. But since the side dock was kind of Ubuntu invention…

The side dock is very neat. But suppose you want sometimes more of a “distraction-free” layout, without this shiny apps panel.
But still want to access apps easily. Also, in Unity there was a simple way to switch to a given app with Win+<number. Like in the screenshot:

Let’s say we are talking about a gnome extension here. Let’s say the dock is hidden by default.
How difficult would it be to make it appear on pressing the Win key (pressing, but not releasing)?
With apps marked with a number, like in screenshot above. If there was no action (press of a number key or a mouse click on the icon), then the dock gets hidden and
the usual gnome dashboard appears. Like this

If there was an action, it gets executed, and the dashboard is not shown. Launching an application, for example, or switching to an opened one.

As far as I know, clutter can trap key-press and key-release events separately. Won’t there be complications due to fact that Win key is a modifier, not a regular key? And how do you feel about this idea in general?