qwertuiop
I believe it is more than feasible for the A380 to enter service in 2006.
Although the aircraft is, technically, a new design, Airbus are continuing the practice of family commonality. This means a large majority of systems and components have already been proven on the existing range. So it's not such the feat of engineering as the 747 was.
With modern modelling techniques and complex fluid dynamics computer models, the majority of the flight handling characteristics can be predicted before the real thing ever gets into the air!
All of which shorten the time needed to get a design off 'the drawing board' and into revenue earning service.
R.