Your best bet would be to do the RGH hack then install freestyle dash. You can then add an USB HDD (I personally have a 2tb eSATA drive in mine). There is a "extract dvd" function in freestyle dash that can backup the games you have. Then when you turn your xbox on, there is basically a list of all games, and they are stored on your HDD.
Research RGH. Personally, I would just buy a premade one from a forum member (about 175ish) and add a usb hdd. There will be a lot of time in research how to do it yourself then the price of the parts and the possibility of making an error and losing your xbox....