There are a great many pc and mac games which have been localized in japan, however these localized games are very low-profile as the japanese computer gaming market is mostly associated with hentai bullshit, but everyone there knows that all the good pc games are made in the west.
So i went to japan a few years ago (wife is japanese) and one interesting thing i saw on yahoo auctions japan was the marathon trilogy japanese version, it went for 20,000 yen (about $200)
I did some more research and found that it was localized by a company called attain, they mostly localize business productivity software but they did localize a few games including
Amber Journeys Beyond
Picture Perfect Golf
Abuse (Mac version)
and Marathon Trilogy.
Here is the translated product description from their archived product page:
Includes Marathon, Marathon 2, and Marathon Infinity - Japanese versions
Pathways Into Darkness - English version
Map winners from Bungie's Marathon Map Contest
Set of Marathon stickers
Collection of maps made by Japanese players, plus replay data and utility programs
The last part is especially interesting as it looks like they might have gotten an exclusive map collection.
So keep your eyes peeled for this box on yahoo auctions japan or in the bargain bin stores if you ever go down to japan, i'll be on the lookout myself although old mac games are just as elusive to find over there as they are in the states, if not more so. but if you ever do find a copy make sure to snatch it up and dump a copy for us while youre at it =)