December 2005: The Olivetti MS25 Premier, and the Rover 5000
This pair of models is presently available in the United States through various sources.  The Olivetti machines are not only available through the official Olivetti network of dealers, but are also to be found at various online bulk sales / discount sales websites.  On the other hand, the Rover 5000 is available only through similar online discount outlets.  No one outlet appears to be offering both brands.

Now, the really interesting part.  Both of these models -- the Olivetti MS25 Premier, and the Rover 5000 Super De Luxe, are manufactured as two different typewriters.  You did read that correctly; there are two mechanical designs being built, and both of these designs are being marketed under both (exact same) brand and model.  Obviously, some proof and some explanation is necessary.
We (my father and I) recently ordered a brand new Rover 5000 from the Dr. Leonard's catalog as a kind of fun thing.  I have all of the other machines recently produced -- and although the shot in the catalog matched the Rover 5000 I already owned (seen at left) we did it anyway.

Click here to view the actual online page wherein you can order this machine.  Note some of the features, and compare them to the Rover 5000 you see here.  The machine pictured here, and the one pictured in the advertisement, are identical in every important (design and mechanical) way.
Here is the machine that arrived.  You can see right away that it is not the machine shown above, and if you looked at the link provided you can see it isn't the same either.

What gives?  Is this misrepresentation?  NO.  It isn't.  Why not?  Because things don't work the same in communist nations such as China, which is where these machines are made.
One of the fundamental differences in communist societies has been, and continues to be, the organization of bureaus and manufacturers engaged in export.  Very often, sets of requirements are issued for a given product, or prospective product, and then production is set up at one or more locations in order to satisfy these requirements (actually, whether for export or for internal use.)  But --- the bureau is responsible for the design and its execution.
On the left, and shown as a supporting example, is a clip from a sheet included with a typewriter called the Omega 30.  This machine was made in Bulgaria, and was actually built by what had been called "Typewriters Works, Plovdiv" but by this time was called "Plant for Typewriters, Plovdiv."  Note the bottom of the sheet, though; the exporter is listed as Isotimpex, Bulgaria.  It appears as if this concern actually owned the rights to the original brand name of MARITSA normally used on these machines.  The exporter and Isot State Economic Association (who operated the Plant for Typewriters, Plovdiv) were actually arms of the same large conglomerated socialist-style bureau.  THUS, while all are linked, the actual entity owning the actual name was the EXPORTER, and not the manufacturer.
Now that we see that it is sometimes NOT the actual maker, but some other agency, that owns brand names in foreign countries, we can understand what is now obvious, which is that the ROVER 5000 Super De Luxe can actually be TWO DIFFERENT MACHINES.  One of these is indeed the old Rover 5000, which is well covered in several places on my websites; the other, which is the one actually received and shown above, is also Chinese-made but is derived from Brother designs.
Although the bodies are different, comparison of the machine pictured above with the one you see here proves that they are mechanically the same machines.  The machine at left is a KMart 300 Deluxe 12, which is a rebranding of the Brother 750/760 series from the 1970's. 

Brother began a cooperative venture with Chinese concerns many years back, and began manufacturing manual portables in China.  Eventually, Brother sold out its interest in the product, and rights, to the Chinese concern.  The actual manufacturer of the machines has changed several times -- China has been undergoing periods of semi-privatization in the last ten or fifteen years, and firms tend to change names there rapidly.  Even with that, though, the fact remains that this machine and the Rover 5000 Super De Luxe are the same in every significant mechanical detail.
Again, to reiterate, this situation wherein one orders a machine pictured in a catalog and receives something different is not mis-representation.  We now have shown how the production and branding works in such situation, and the fact of the matter is that both machines actually have the same features -- rapid space, variable line spacing, and so forth.  Each will do what the other will do, which is why the exporter using the model Rover 5000 Super De Luxe can supply either machine as needed, or as available.

Now, this situation is doubled when we consider the other new machine available, which is the Olivetti MS25 Premier.  It seems obvious that Olivetti has worked with exactly the same exporter, and that in identical fashion, those ordering an MS25 could receive either a Rover-based machine or a Brother-based machine indiscriminately.  You can use the two links below to view two internet advertisements for the Olivetti MS25 Premier.
to see an Olivetti ad clearly showing the Brother-based variant.  (Jay Respler site!)
to see an Olivetti ad clearly showing the Rover-based variant.
This ongoing mystery has finally been untangled.  Who would have thought, right here at the end of the running history of the manufacturing of manual typewriters, that we would have a "first ever" event?  Yes, I say "first ever" because, to my knowledge, at no time prior has a model of typewriter been supplied as one of two mechanical designs.  Normally, they'd have to be different models -- and considering the differences between the Rover-based and Brother-based machines, they'd actually have to be not only different models but wholly different brands.  It thus happens that there are actually, in a technical sense, FOUR brand new machines available -- Rover and Brother designs each either labeled as the Olivetti MS25 Premier or else as the Rover 5000 Super de Luxe. 
February 2006:  A further brand-new typewriter for sale NOW... click here.