I don't.pretend to know the details of Smithsonian but I would assume that its run by intelligent people who are more capable than both you and I are at figuring out how to make space for CoP.
Well, personal insults aside, how about actually taking a look at the museums themselves and determining that before firing up this rumor for the fourth time.
Air & Space Museum- At capacity, with absolutely no room in terms of floor space and building design.
American History- The same, plus it just complete a two-year, $85 million renovation that saw the museum closed for two years. Pretty sure there's nothing new going in there (if any space was available).
Natural History- It too underwent a renovation not too long ago, and likewise has no space (plus, CoP doesn't exactly fit either).
Ditto for the National Portrait Gallery, HirshHorn Museum, Freer and Sackler Galleries, or the National Gallery of Art (which technically isn't a Smithsonian Museum, but it is on the Mall).
Now, that leaves the Udvar-Hazy Annex in Northern Virginia, and it could hold CoP. Of course there's the pesky issue of the hundreds of various airplanes, helicopters, missiles, rockets and oh yes, the Space Shuttle Enterprise taking up precious space.
So, where will these imaginative folk find the room?