For a better version of this poster, seen in a shop window in San Francisco yesterday, see this Flickr site.
The original slogan makes its appearance at a Canadian liberal convention (search or scroll down).
Not a huge amount of other activity going on, although it still makes its appearance in many personal blogs in many different guises:
Mass Communications Academic, @MMUBS. British Home Front Propaganda posters as researched for a PhD completed 2004. In 1997, unwittingly wrote the first history of the Keep Calm and Carry On poster, which she now follows with interest.