Is there room in there for a more expensive BMW? Maybe. Mercedes did fail with Maybach when they tried to take the S-Class too far upscale. Rolls Royce is currently positioned as filling that high end sphere and doing well in that role. BMW is all about variants and squeezing out sales but how the 9-Series will differ exactly from the 7-Series and Rolls Royce Ghost remains to be seen. The one area we do know about is the styling which will be based on the Gran Lusso Concept.
That concept car actually made a bit more sense as it was a coupe and if it were produced would fill the 8-Series gap. BMW does not have a competitor for the new S-Class coupe. If BMW is making a 9-Series though it is a fairly good bet that a new 8-Series will come as well on this same platform.
Twin Turbo V12 power from the N74 seems certain. BMW would likely tweak the larger N74B66 for the 9-Series and leave the smaller N74B60 for the 7-Series to create a point of differentiation that is larger than just cosmetics. That would mean the Ghost and the 9-Series would share the 562 horsepower 6.6 liter version of the V12 which no BMW model currently utilizes.
Will the 9-Series cannibalize Ghost sales? Will an 8-Series make a comeback? Is this even a good idea? We will have to wait and see how this all unfolds.