Yeah, just an update. So I bought a 2012 Stark, Navy/Small (my measurements are like 5'11", 155lb + 35.5" chest) and the Small fits very, very slim.
It looks great unbuttoned w/ a t-shirt underneath and slightly tighter when buttoned up, but I can't imagine layering a dress shirt underneath, it would be too tight + awkward looking. I would opt for a Medium in that case.
As for length, it's perfect. Falls over the belt for me.