Iron Man's REAL suit!

While it may have been built and "reality tweaked" by Stan Winston, this is quite irrefutably based on Adi Granov's Iron Man suit first seen in the "Extremis" storyline which debuted the current sell-out run of Iron Man.

I suspected they'd go with this since Granov drew the teaser poster in July and as I hoped they kept the circular Uni-beam chest -light as opposed to the modern triangular version. The shoulder plates and knee-joints are more like the armour worn by Iron Man in 2002 as opposed to Granov's later designs.

It was obvious that there would be tweaking and the armour wouldn't match exactly to an armour in the book but I'm still genuinely surprised by how faithful Favreau is to the source material.

Source: AICN (Read my comment there!)