I don't know any collectors in Japan, though I know there are plenty of Japanese collectors who go into card shops and drop a few hundred dollars or more on the latest product looking for big hits. And there are people who like to get cards graded for various reasons.
So I'm putting this out there for anyone into this - are you interested in information about the new service? If you are, let me know - I'll pass your name on. I'm not sure if being an "early adopter" will mean any kinds of discounts or anything, but since I'm going to be too busy to post anything else I thought I'd share. Just send me an email!