FWIW, it you're looking for an imported Japanese maple and have $830, you might check with Brussels or another high end supplier in the US. They may already have stock similar to this. Personally, I don't think this particular tree is worth all the effort...
If you're still interested in importing yourself, this is really the guy to talk to in Japan:
http://www.j-bonsai.com/
The site's owner is Yoshihiro Nakamizu. He's connected to many "name" bonsai nurseries over there. There is no language barrier. I've worked with him before--not on a tree, but on pots. He made things very easy. Prices aren't all that high either.
Another person closer to home you might give a call or an email to is Bill Valavanis up in New York.
http://www.internationalbonsai.com/
He tours Japane regularly and can import for you from select sources in Japan. I had a friend that Bill imported a Korean Hornbeam for way back when. He used to take orders for trees before each trip and set up importation. Don't know if he's still doing that, however.
In either case, you're more likely to get a better and easier deal than that web site.