its a great idea.. i think its in the new skunk magazine they have an article on this thing called rpm.. or rotational plant mover i think it is.. the rpm takes you idea even further and simulates the movement of the sun in the sky and even has a built in rez for hydroponics grows..
its not the fact that you need more light, moving your plants does much more than that.. it allows you to have no shadow areas in your garden, and eliminates the wall plants that i hate..
i'm not sure how much the rpm is as the website looks like it just went up and didn't have much info on it honestly, but i think your on to something here..
if you get a good drawing or whatever, pm me as i would love to see what the mechanic at my work could come up with for me..