in no way does this mean that I could actually pull this one off, but certainly someone should be able to.
You would have to write a LOT of custom drivers for controllers, motherboards, nic cards and just about any other piece of hardware that is not typically found in an xbox, but the xbe is basicly a gui interface that could run just like any OS off any hard drive.
I wouldnt expect anyone to really dive that deep into trying it any time soon when its much easier to just mod your xbox & be done with it and unless you can write fluently in whatever programming language they used for the xbox I wouldnt even bother to try it... but yes it could be done.
(and ya know... I would love to see how some of these games run on my 3 gig proc with 1.5gigs ram & 256mb video card)