The problem with this in terms of energy output is conservation of energy. In more conventional energy generation, we take energy in one form and convert it to another, far more 'useful' energy. Generally speaking, this means taking heat energy and converting it to movement (cars and trucks) or electricity.
The stored heat energy is in the form of coal, oil or gas. More recently we've been converting direct sunlight (heat) to electricity as well, and in Australia, we've been converting kinetic energy (rivers et al) into electricity for some time with systems like the Snowy River Hydro-electric system. Many other countries are using dams for exactly the same reason.
Why is all this important? Because even though we say we're 'generating' energy, we're not. We're really releasing the stored energy (or harnessing existing kinetic energy) in a form that can be used against a wide range of applications. In the example you're describing above, this won't happen. The amount of energy created by Tolkien rolling over in his grave would inherently be less than the energy used to print the book in the first place, not to mention laptop power used to write it in the first place, etc. Then there's Shipping Kilometres (look up Food Miles and Transition Cities to see the REAL cost of distribution in energy terms) and it becomes clear that you'd never get the same amount of power out of grave rolling as you'd need for the book production to do it, especially at a single roll per book sale.
Kindle might make that a little more efficient, but you couldn't power a kindle on the kinetic energy generated from a single roll. Particularly when you consider that a dead body will lose water pretty quickly, so the mass of a corpse would be substantially lower in time, meaning that the angular momentum of the roll would contain MUCH less energy...