The orginal plan was so.... The AmigaONE motherboard was supposed to have a socket to hook up a a1200/4000 motherboard so the AmigaONE would get access to all its chipset and such, so it would be fully compitable..
But sadly it didnt end up this way... Now eyetech are supposed to make a 1200/4000 addon card for the a.one, but i honestly believe it will never see the light.... :-(