My guess: Marko Ahtisaari Edit: Reasons:UI/UX of this device is rumored to be awesome (as K123 has said) and he is responsible for UX at Nokia he was not on the speaker list from the start, so there was a change (Elop -> Ahtisaari?) he is very passionate about disrupting devices (see his talk at Le Web '10)
However, we do learn that Nokia’s International nDevice of mystery “will be unveiled and demonstrated for the first time by Kurt Bonnici, product and technology marketing manager at Nokia Australia”. Following this demo will be “a live broadcast of Stephen Elop’s keynote speech from the Nokia Connection conference in Singapore.” Nokia has advised the press that the information is a technical session only, stating: “Please note this will be a product demonstration only. “In his role as product manager, Kurt will only be available to answer technical questions relating to the new device.”