Of course getting both a new stock HD and a new eeprom will work, this is basically buying a new Xbox sans motherboard, DVD-ROM, etc. I think what we're trying to figure out here is exactly what MS currently cares about, and what is being used to track modded 'boxes. I also am not convinced that it's safe to use your old GT. I think there is merit to the idea that this puts you at increased scrutiny. All I can do is report what happens to me, and if I get banned... so it goes. But I suspect there are a lot of us in my situation who held on to our old HDs, and it would be nice to have one less thing to go out and buy.
-Rob