Over at his
website, movie concept artist Robert Simons has posted multiple images of his
concept art for Transformers: Age of Extinction. His art mostly focused on designs for Bumblebee, Optimus Prime, Lockdown and his ship. Of note though is the dates on the art are around 9/27/2009 which is two months after Revenge of the Fallen was released. Does that indicate that Lockdown was in early consideration for Dark of the Moon? Maybe the TF4 story was being tossed around for TF3 until chose a different direction? Any case you can hit the link above to view his work or the mirror of the images
here.