My arm was getting tired, so I decided to over-engineer my coffee grinder. It already runs on a standard screwdriver bit hex, so I was actually pretty surprised that nobody else beat me to it.
I've been tempted to do the same thing for years with my Hario Skerton and a Makita 12v driver drill. It's 400ish cranks every morning. I would imagine a finer grind with an espresso bean would take you much longer. As it is, the morning grind is part of my routine and a much as automating the process, having my drill shared between the garage and the kitchen would introduce it's own issues.