All that stuff sounds really interesting and not off the wall as some other ideas are. But it will require a redesign of the MiniMig itself. The primary reason is the XC3S500E - it is not pin compatible with the XC3S400 used today. By doing that, we could put the ARM and all the other new chips on the mainboard too...
Edit: if someone takes care of the core software, I would happily create a new Mini-ITX out of this... :-D