We've seen a ton of Iron Man 3 concept art before — but we didn't see the concepts from suit designer extraordinaire Phil Saunders... until now. Saunders finally released some designs for Tony Stark's cutting-edge armors, and they are glorious.
One interesting piece of information that Saunders released, along with his early designs for Extremis soldiers: originally in the film, Extremis was going to be based on nanotech, true to Warren Ellis' original concept. Saunders writes:
In early versions of the script Extremis was based on Nanotechnology like in the comic book, and would have constructed some sort of internal armor structure to grant the enhanced soldiers super-strength and near-invulnerability. thematically they would have been a reflection of Tony Stark, wearing their "suits" internally rather than externally. Makeup would have subtly suggested that structure by deforming their skin in a mechanical way.