The video is expected up sometime after GDC. But g4tv has some screens of Epic's latest tech demo, now working with Nvidia, DX11 and a ton of other awesome pretty stuff.
http://www.g4tv.com/images/3985/Unreal-Engine-3---Samaritan/66191/
http://www.g4tv.com/images/3985/Unreal-Engine-3---Samaritan/66191/