But as far as I know, the -900X isn't proposed with a 3rd overwing, but rather an additional type I door aft of the wing deratable to type III with lower seating densities (i.e. true 2 class), is it not? Even with the additional door, surely the airplane isn't long enough to get 220 seats in, but more around 205-210, I'd have thought (and that in a European charter type configuration).
747Focal - I still maintain that the 737NG has exceptions due to grandfather rights in the areas that I mentioned - can you tell me with 100% certainty that that is not true? If so, then I fail to understand why the Seattle engineers have been cagey about answering exactly those points - i.e. what those exceptions actually are.