Concept artist Emiliano Santalucia
has posted some new concept work that he did for Hasbro during the development of Transformers Dark of the Moon. There are two pieces of artwork posted, depicting the evolution of a piece titled "Autobot firefight". It's a pure pre-visualisation piece from when ideas were still being batted around, depicting a new team of Autobots. At the time this was done no specific characters were defined other than the team wanting them to be new and look cool, which they certainly do in this piece.
Of interest is that while this is a very early concept, you can see a lot of what made it into the final cut - namely this seems to represent the battle of Chicago.
For those who like to see the progress of a piece of work, Emiliano has also posted up his initial sketch of the piece which you can compare to the final work to see how the ideas evolved during the design process.