Meridian is doing exactly this! Meridian is a small commodity to create virtual hotkeys by using the mouse. You draw a symbol and Meridian is starting the requested action. Since the starting point and the direction is also important, there are countless combinations you can use.
I promise! You'll love it. Flipping screens and windows, closing windows, quitting requesters, starting programs and actions just by moving the mouse. No visible GUI, dock or something like that. Just the mouse pointer on screen. I am using Meridian now for around 24 hours and I can't live without it anymore.
Meridian allows to execute CLI and Workbench programs. It's also possible to translate the mouse gesture into a new key which will be treated by the active application as if the real keyboard key was pushed. A great feature is that Meridian provides a massive bunch of internal macros. So you can close window, flip screens and windows and much more.
In the top left of the window the Meridian is shown. The white arrow defines the start point and the direction. The black arrows are the movement successors. To reproduce this Meridian it's required to move the mouse like an "U" and it's required to start top left.
It's possible to combine the mouse gestures with tasks, so it's possible to define the same mouse gesture multiple times for multiple tasks with different actions.