Neogaf has once again does the brunt of the work for us, but we're pretty confident we would have figured this one out regardless. It's about as subtle as a zombie bite to the face.
First, there's the "NO HOPE LEFT" graffitos—with the first "O" turned into the Biohazard (Japanese for Resident Evil) symbol—popping up in the UK, Europe and Asia. The above video has the site nohopeleft.com in the description, which heavily features the date Jan. 19. That just happens to be tomorrow. And the website was reportedly registered by the same firm that did the viral marketing for RE: Operation Raccoon City.
Most telling of all, The Sixth Axis actually got the company that owns the space one of the ads is printed on to admit that Capcom is behind it.
Overall there's little doubt there's a Resident Evil announcement coming tomorrow, but will it be RE 6 or something else? If you've got any more clues, let us know in the comments or on Twitter.