Well there's not much you can do about the sides since the superdrive and ports are on the side if you're considering the invisible skin..
there is a solution though, if you don't mind a few millimeters of bulk...Speck Hard Shell Case. It's costly...$50 + shipping but it protects the macbook very well. I actually have one just sitting around. New, unused that I'm willing to sell as I don't have a use for it.