Its being called XPeria although it cannot be confirmed till SE officially announces the phone. It's based on the 1GHZ Snapdragon and has a 4" display just like the Toshiba TG01, but runs Android instead of WinMo.
Although the UI looks sweet and I WOULD DEFINITELY try it in person... I feel that they need to cut down the transition times. It all looks nice and cool at first, but in regular use long transitions between screen tend to get irritating.
But Yeah... this really really looks awesome... and so far the specs also look promising. They need to time it right and price it right.