That's why I did the 'basement apartment window' look. It's the only way to get any light down there. It's easy - you knock out a couple of foundation blocks, put walls on the inside, add a window (you must use move_objects on, then draw a perpendicular wall to make the window show up), and add a fence to the outside. It doesn't take away from your interior space and adds not only light but a little architectural interest.
Hmm, interesting idea. I'll have to try this when I get home. I hate basements because they are usually so dark, and I don't like putting in a lot of lamps.