This is actually both a first and last for the second-generation BMW Mini. It is the first time there has been a two-seat Mini with a soft-top and it is also the last model to be spun off this platform: work is already well underway on the third-generation model.
However, car companies are no strangers to developing a last-hurrah for a model range. Both Porsche and BMW tend to introduce their most extreme versions (e.g. BMW M3 GTS) towards the end of the model's life, and Ford always seems to launch a Focus RS even as the next-generation Focus is starting to roll down the tracks.
The Mini Roadster is basically the convertible version of the 2011 Mini Coupe - minus the strange baseball-cap roofline. It has a lowered windscreen and, paradoxically for a roadster, a very large boot, thanks to the absence of the rear seats.