Heres another interesting Possibility people on my myspace forum titled Cloverfields Monster Theories have been posting a picture of this monster who was created by Peter Konig who is Tippetts art director for the upcoming, top secret JJ Abrahms production Cloverfield. Here is a link to the website from where this picture originated. http://www.conceptart.org. Dont know how true it is but looks closer to what I see in the trailer then that rancor wanna be.

The photo is below and frankly the fact it came from the art directors website is damn good indicator this may in fact be.. CloverField!