"thethirdfloorinc.com"에서 공개한 "Cloverfield"의 Previsualization 이미지

 The "previz" work for 1-18-08 / Cloverfield was done by a company called
The Third Floor.

Previsualization is a film making technique that uses 3D computer graphics to create rough
versions of movie sequences - usually complex shots incorporating visual effects or stunts.
This allows the film producers to see a rough version of the sequence before the costly full-scale production starts.

Cloverfield is mentioned in the Bios of Barry Howell and Nick Markel, and in the News section:

After being tapped by JJ Abrams’ production company to work on the super-secret “Cloverfield” trailer, (as seen in front of Transformers); The Third Floor delivered previs for the entire feature – coming soon (01-18-08?) to a theatre near you!

The Third Floor's other works include: Fantastic Four: Rise of the Silver Surfer,
Pirates of the Caribbean 3, Evan Almighty, Beowulf, Final Fantasy: The Spirits Within.

The Reel section has a six minute video of their work, including some very short scenes
of the Cloverfield trailer. I created a YouTube video with just the Cloverfield footage here.

UPDATE: The Third Floor has asked that I remove the YouTube video.
However, you can still see the full six minute video on their site.
The Cloverfield scenes are at 0:26, 1:39, and 5:36.

* Special thanks to Robbie for emailing about The Third Floor!