If you use a 2.5" hard drive you dont need a 12volt power source, so you could just use it thru the usb kind of like they do the wii hard drives... and make it internal , just would have to cut the end of the usb end off that would go in to the usb port and hard wire it in. then it would be inside all together nothing sticking out, just dont know where you would put it . being theres not much room inside the xbox 360. would be like using a thumb drive. all you would need is a enclosed hard drive case would have everything you need to do this.