Slashfilm has an exclusive 10 Cloverfield Lane poster created for the IMAX version by UK artist Kevin M Wilson (aka Ape Meets Girl). They also have a short interview with the artist.
The poster has some hidden Easter eggs from the movie, and other things...
Check out the interview and full-sized poster at Slashfilm.com
UPDATE: A higher-quality poster is now available, which I have uploaded to my Imgur album.
UPDATE 2: Kevin Wilson, the actual artist who created this poster, has responded to a few of the comments in the post! Hi Kevin!