http://www.interstudio.co.jp/top.html
Recently shot green screen at this studio... 30/40 mins drive on the highway outside central Tokyo.. pretty easy to find.They can paint the studio for $10,000 US or they have very big green drapes that can be used,I think ours was 20m X 15M.
BUT... no one speaks English.. which might go for all Studios in Japan! and they dont rent camera gear,but might be able to rent in for you,not sure.
I would advise you will need a local fixer for sure..getting off the plane and hoping for the best wont work .. many places will also want payment in cash..