i dont know if this will do anything but here it goes.
on the psp, when you want to downgrade from 2.0 to 1.5, there are files that you put on the memory stick for the operation. to get the downgrade started, i remember highlighting an image file. as soon as i highlighted that image, no buttons were pushed, it started the downgrader. could we use this setup for the 360. maybe with the external hard drive onlying reading .mp3s and pictures.
also another idea, i was looking at two xbox 360 offical magazines. in one of them it states that the 360 hard drives are meant to play on every 360 system. (yes we already knew this).
in the other magazine, it comes with a dvd that can play in both xbox and xbox 360. any way we could use this this.
again only ideas, im a noob when it comes to this stuff but i love the modding community.