The video link below shows some footage (interviews with Boeing managers), and might provide some perspective...
As for interior volume, carrying wing and fuselage sections of the 787, there is a scant few inches on the top and sides when the loading system puts the cargo in the belly of the beast.
Another great video (excuse the drama provided by the very enthusiastic BBC reporter!!)...but factually, very correct.
BBC News - The 'pregnant plane' that can give birth to a new 787