The Gamestick is a nice option if you're looking for something a bit more mobile, because the console itself is nothing more than an HDMI thumbstick, which can be stored inside the controller if you'd like. If you want one, it will cost you $79 for the pre-order. And, there are some peripherals available as well, including a case for $9.99, or a dock for $24.99.
The dock may seem a bit expensive, but it's actually pretty cool. It allows for easy charging of the controller, added storage (up to 64GB), and connect other peripherals through USB ports. Not too bad.