I know I'm a bit late to the party, but I've also been looking for a high power 5V solution. After reading about [how terrible knockoff power equipment can be](http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html), I was a bit skeptical about buying [what ikku suggested on ebay](http://raspberrypi.stackexchange.com/a/4574/8405).

I found [this](http://www.adafruit.com/products/658) from Adafruit, which should be a solid product. It's a bit more expensive at $25, but power supplies aren't something to skimp on. You would need a breakout for the plug on the end of it.