Uwajimaya is a local Asian supermarket. It is huge, it has just about everything. We found this there:
That is indeed a ginger ale flavored KitKat. It was more delicious than it had any right to be. They also had Sweet milk tea flavored (with pictures of those British Palace Guards on the label) and one with no description, but a picture of mochi, so I am guessing they make a sweet bean paste flavor (I can't decide how I feel about that one, it will be either wonderful beyond all reason or a flavor travesty of epic proportions).