A laptop cover can be as simple as an envelope made of denim or upholstery fabric, or a super-custom creation with pockets, zippers, padding, handles, etc. I am making custom covers for e-readers (NOOK, KINDLE, ETC). Due to the small size and very fragile nature of them I am adding padding and a layer of thin plastic stiffener to protect the screen.
They only take a couple of hours to make, including pockets for library card, etc. They really aren't that much work to make.