Optimus Prime is a Peterbilt truck. This vehicle was previously seen in Spielberg's film DUEL, in an ironically antagonistic role. This raises for me an interesting premise: what if automobiles that previously appeared in Spielberg films were cast as Transformers? The most obvious one is the DeLorean. The Autobot inventor Wheeljack, of course, would be perfect for a DeLorean, and not the 1980s but this 2005 concept DeLorean: http://www.businesspundit.com/wp-content/uploads/2009/01/delorean1.jpg It's a magnificent if somewhat retro vehicle, and you could load props on it like the Wreckers have to make it resemble Wheeljack's famous gadgets and stuff. Have it hover, or space bridge its way across cities; something that invokes its crackpot-inventor nature of Wheeljack and also homage BTTF. Ah, it was just an idea. But do contribute anything, if you can.