The Tumi Electric Adaptor looks a neat gadget to pop in your bag when travelling. Rather than being separate units for separate plug configurations, this is a one-piece solution offering four plug configurations. All you need do is push the slide switch to extend the particular configuration needed.
Tumi claim this plug will provide power connectivity in 150 countries. Its dimensions are 70 x 57 x 50 mm (H x W x D), and it costs US$75. You can buy the Tumi Electric Adaptor online at Amazon.