Metropolis Part III?

[RaiseTheKnife]

I speculated on this in 1999 and MP confirmed at the time that it was intended only to be two parts.

[jonny108]

I really doubt it is Metropolis Pt. 3.   

[The Dark Master]

A band should never EVER make an actual sequel to a concept album.  If a band had planned to make a series of concept albums from the start (Rhapsody, Dominici, the original Avantasia duology, Trans-Siberian Orchestra's Christmas trilogy) then it can work, but only because the individual albums were initially intended to be part of a greater whole anyways.  Even tying multiple concept albums together via a unified cosmology and recurrent themes (a la Ayreon) can work, but generally speaking, a band should not make a sequel to a concept album because many concept albums are stand alone pieces of art with completely self-contained story arcs.  Making a sequel to a complete story that was never intended to be continued in the first place is a massive disrespect to the original work itself.  Of course, a band can make multiple good concept albums that are each completely separate from each other (Savatage made several of them), but to make a sequel to what may be considered to be your masterpiece for no good reason other then you can (read:$$$$) is always a bad idea (I'm looking at you, Queensryche).

[RaiseTheKnife]

I would cite King Diamond as an exception to the above mentioned rule.  He has some good concept albums and sequels based thereof.