We can put this down as one of those things that are so simple it's hard to believe that no one has done it before. Anytime I plug in a new notebook or gadget in my house I have to unplug something else. All my outlets in the office are full.
Elecom has a new device that plugs in between the cord that runs for the wall to your notebook power brick and the power brick. The electricity flows through the adapter and provides power to the one or two additional plugs the adapter adds.
The adapter can be purchased in dual prong or grounded three prong styles. Pricing is unknown, but they can't be that expensive. I want a bunch of these things.