Kim Stanley Robinson used this idea in his Mars book too. Hopefully someone will be able to get this concept working in the not too distant future. It would be a great way to get around the cost of hauling things up out of earth's gravity well.
Its about time i say. The initial cost would be enormous, as would be the benefits.
Can you imagine a cheap way to build and maintain L-5 Habitats, space stations, and a permanent lunar colony.