You can do something like it with PowerPro, which offers buttons with tooltips rather than a menu as such, but PowerPro is just too hard for most people.
hehe I use Autohotkey AND powerpro and the only hotkeys I have programmed are ctrl-shift-c to center the active application and ctrl-shift-space to kill the active application. Why? because they fit my left hand, aren't used by anything else and my right hand is (inefficiently, I know) at the mouse 50% of the time. The other hotkeys I use most often are the system ones for cut, copy, paste.
I don't agree that PowerPro is hard, just complex. You must learn what it CAN do, then HOW to do it, then figure out WHAT you WANT it to do. This takes Patience and Perseverance which also takes Time. These things, taken as a group, are lacking for most people. After that, PowerPro is (almost) everything I need. I use Autohotkey because I quite dislike the PowerPro scripting, and I can compile into .exe's and impress my boss!
Speaking of Un*x how about vi? Hotkeys are the only way it even looks like your using a text editor! And how about
Rat Poison for a X window manager? No mouse! (bad graphics, yes, but the idea is solid.)