Yeah, I don't buy the "custom" theory; this thing was definitely planned for sale, even if in limited quantities.
I remember reading somewhere that the blue iron man variant had been cancelled.
Similar to what you've already stated though, they have already announced the IM hall of armor, and stated that Armored Whiplash and racetrack suit Tony stark are in development but delayed for the time being.
I can't imagine that a blue variant is high on the list of priorities right now.