There is a lot of fuzz about special Leica cameras, special editions, special serial numbers. There was a special 0-series Leica build in 1923, one of only 25 pre-production models, that sold for an astonishing 2.16 Million Euro (around 2.8 Million Dollar). Read about it here.
Maybe in 80 years this camera below might be worth something: it is a prototype model of the Leica Monochrom I had a chance to shoot with. The Monochrom (announced in May 2012) only captures pictures in black and white. As an anti-aliasing-filter is not needed, the pictures have much more and finer detail. Because there is no color the problem with noise is also much smaller.
This Monochrome has, as you can see, the serial number P-003 engraved. This means it is the Monochrome prototype number 3. Number P-002 is owned by Leica and was used by Brad Pitt for some time. Pitt is an avid photographer and a big fan of Leica (one of the cameras he owns is a S2).