mavhc: too true! The RPC probably ranks as the most upgradeable (and upgraded) computer in history. Without its unique qualities I doubt there'd still /be/ a Risc OS market.
martin: from what I've read, the latest X-Scale (80331, I think) IS a significant advance on the chip in the Iyonix even though the clock speed is the same. However it would require a mobo redesign, apparently. BTW, has anyone tried to overclock an X-Scale?