That's super neat...but it's $900 for the Canadian version. Since I live in a condo I can't do any major modifications to the wiring anyhow. The power pack I have is very similar to one of the Xantrex models (I wouldn't be suprised if Xantrex was the manufacturer):
http://www.xantrex.com/web/id/63/p/1/pt/10/product.asp

I use it when we car camp or road trip to run the 12V cooler and other assorted goodies. Combined with the 950W inverter generator and a couple of solar panels, hotels are a thing of the past on road trips. Comes in damn handy when the power goes out too.