Amazing what you can find by reading Wikipedia articles. I found that an independent studio called Panic Struck Productions put together a 40-minute Star Wars film entitled Star Wars Revelations. It's about 40 minutes long, and when downloaded takes up about 252 mb.
But it's very good, particularly when you consider that it's a fan film. The computer graphics are without question better than the unmodified original trilogy, and some of the lightsaber fighting is pretty sweet, too.
Because George Lucas allows non-profit derivative works to be created as long as the appropriate credit is given, the film was made possible.