Advanced Japanese Courses

I was wondering if anyone would have any recommendations on advanced Japanese classes in Tokyo. I have a master of Japanese studies degree and speak, read, and write the language very well, and have even worked in a Japanese company for over 3 years.
I am now looking to take my skills to a near native level, specially focusing on vocabulary use and expressions. There are a lot of schools out there, so if anybody has any advice on this, I would love to hear from you.
Thanks!

The more advanced you get, the more difficult it becomes to find "courses" - even among advanced students, the individuals' levels or strengths and weaknesses (and their interests, whether for business use or for cultural interest, etc.) vary tremendously that it gets difficult to put together a class or a course for a group of learners. I would say you would need to ask a school about how "advanced" their advanced level classes are, and possibly you might want to ask for a private tutor arranged by the school.

I know someone (though some time ago) who asked Naganuma School in Shibuya for private lessons.