Muji has sold the London map playing cards since late 2010 and I have purchased this in February 2011 since. The Hong Kong Muji does not sell the other sets ut the muji.us sells Paris, Tokyo and New York.
The face of each card carries marking and a section of London map. If you arrange the cards in order: Spade, Heart, Diamond and Club from A to K, you will see the map of Central London. It will be nice if the back should have been printed a whole Central London map rather than being empty without any design.
(East to Design Museum; West to Kensington Palace; North to St. Pancras; South to Westminster)
Where to buy: www.muji.us or your local Muji store
Close-up of the map: