As I've stated before, there is only one building in the Smithsonian lineup with the "space" to house Cop- the Udvar-Hazy Air and Space Annex at Dulles. It has the space, were it not for all of the existing (and permanent) exhibits already in place. No single Smithsonian Museum building on the Mall has that type of space available, especially after two of them (American History and Natural History) have recently undergone renovations to both their exhibits and internal architecture. . . .But of those three I mentioned, the only one that thematically fits is the American History museum.