Here are some suggestions of Japanese roasters (or at least, roasters with Japanese operations) who should have good espresso blends. All are Tokyo-based (and have retail cafes where you could try the coffee) -- not exactly Hiroshima, but a lot closer than North America or Europe:
- I can personally attest that
Paul Bassett has an excellent espresso blend;
-
Zoka has a Japanese operation; I have not tried any of the output from their Japanese roastery, but I have had good experiences with their coffee in the US;
-
Bear Pond Espresso is a place which I have heard good things about but have not had a chance to try myself. It is not clear to me whether they ship out orders of coffee or only roast for their own cafe, though.
I hope these are helpful to you. There are also some places in Kansai (at least one in Kobe, if I remember correctly) which I have heard good things about (but again I have not tried them myself) -- I can try to dig up some info if you are interested.
Navin