We can see plenty of influence from both Gingerbread and Honeycomb here, as well as four shortcuts on the bottom (a definite bump from the two found on vanilla 2.3). There's a new Google Apps icon which opens up a tray containing a number of featured services put out by the search giant, and long-pressing the home button brings up a vertical Honeycomb-style multitasking menu. The notification bar, camera UI and other menus also have a much different look. Granted, all of this could just be a custom ROM built to emulate the latest Google dessert, so we can't be a full hundred percent certain that it's authentic. If it's not, at least we can give credit for it being incredibly elaborate. Enjoy the video and additional screenshot below.
Update: Our anonymous tipster has confirmed to us that shortly after we posted this video, his Nexus S was remotely locked and wiped. You can follow the entire saga over at this XDA Developers thread.