I have an I dea that would be alot cooler, mount the biggest lcd screen on top of the 360, internalize the hard drive which there is already a tutorial on, then make a custom battery pack that goes where the hard drive was but take up the full area on the end and maybe make the batt. a little thicker than the hard drive so you can pack as much li-ion batteries that you can. Heres a mok-up that I did on photoshop minus battery pack.
*EDIT- Best thing about it, no cords if you have a wireless controller.