After reading speculations about the A3XX in that forum usually I decided to inform you about thess FACTS:
Right now, Airbus and many large carriers (Air France, ANA, British Airways, Cathay Pacific, FedEx, JAL, Lufthansa, Singapore Airlines, United and Virgin) are working together on the development of the A3XX. All these don't do that for fun but for the reason that they are interested in that plane.
About "TOO BIG" speculations:
The A3XX-100 would offer 550 seats in three classes at a range between 14.200 and 16.200 kilometers. Following A3XX-200s would come out as freighters or combis also.
Regarding many routes where B747-400s are used several times daily with seating of around 400-420 I don't think that 550 seats in three classes would be too many. Please note air traffic is increasing permanently and don't forget the A3XX comes out in about five to six years, not tomorrow. So I think the growth will require larger aircraft in the future.
And even in case that 550 seats aren't required in five years, many airlines think of more comfort offered by a larger aircraft. The A3XX could be flown with 450 passenger seats but together with lounges, little bed rooms, bars, emergency room and more facilities. Virgin Atlantic will offer a casino abord the new A340-600 already...
A combi version could help some airlines to fill the plane in the first time also.
Of course, Boeing can strech the B747, yes they will do it. But right now airlines are working together with Airbus on a large plane which shows they are interested in something VERY new, in something developped for the next century. A B747-500/600/700/800/900 would be good, I'm sure, but it is nothing really revolutionarily new, it's something developped in the 1960s.
And you can be sure the price is not the only aspect which airlines take care of in case of buying an aircraft.
And Boeing and Airbus already had several wars with selling prices, the result were losses at Boeing, not at Airbus.
The market for the A3XX will be certain and nobody can really claim we don't need larger aircraft in the future...
Me & You & a Plane Named Blue...