Sony Ericsson brand and what looks like a 3.5mm headphone jack -- the latter of which would suggest that this phone is no more than six or seven millimeters thick. Even more enticing is the promise of "more entertainment at the touch of a button," suggesting some processing and graphics firepower contained within as well -- could it be SE's answer to the dual-core LG Optimus 2X? We get the feeling we'll love this thing whatever the hell's inside it.
Update: Closer investigation of the imagery has led us to believe this is probably the Anzu / X12 that we first saw back in November. That device's claim to fame was a 4.3-inch display allied to a "very, very thin" profile.
Update 2: The mysterious handset has now been revealed as the Sony Ericsson Xperia Arc.