The motivation for this project comes from the irritation of using keyboard when creating art. Usually I use a drawing tablet's pen in one hand and keep the other hand on the keyboard. It's necessary because working without hotkeys would be excruciatingly slow. Keyboard is a universal tool. Good for a lot of things. Perfect for typing... nothing else though.
Keyboard layout isn't optimized for tasks like creating art. Often times CG programs use mnemonics to help you, i.e. in Photoshop the Brush hotkey is B, while Eraser is E. This logic works well if your goal is to learn the software hotkeys. It isn't ergonomical though. Usually you use way more hotkeys. That means you jump all over the keyboard. Some of the hotkeys are combinations, like CTRL + S. It adds a lot of friction when you work. Everyone gets used to it but I it never gets comfortable.
That's why I'm experimenting with things like that. The amount of functions/tools you use in those programs is limited. 90% of your work you switch between those again and again. Those tools should be easily available and give you control appropriate for the task (some tools are more analog in nature).
I think the Wii Nunchuk is a nice base for experimentation.