I have spent a bit of time putting together the batting and pitching stats from Japanese pro baseball from 2005-2010. I've uploaded it onto Google Documents so that you can use it as well. The English names are all pretty-much wrong (I guess there are a few correct ones in there), because there are over 1000 different last names alone, and translating them would have taken a long time. However, the names there should be usable for doing stats, and searching for the name of any player on google by copy-pasting the characters should get you a site with the proper English name.
Also, Japan tracks "Hold Points" which are holds + relief wins. Useless stat, but it's in there.
All data was retrieved from the NPB homepage.
Please feel free to use it however you'd like, and I will start delving into it myself in the near future. You can access the Google spreadsheet here.