http://kingfisherwoodworks.com/
You can get him a lower grade bokken somewhat cheaply, and have something personal engraved on the handle from 4 or 5 different lists of japanese characters grouped by conceptual family shown below:
http://kingfisherwoodworks.com/inscriptions.html
The hand cut options are pricier and would make a better gift whenever you think he'll be able to appreciate it.
Regardless of finish they are tough, and beautifully balanced. Good luck!
(Later on I would also suggest finding a nice set of freezer gel-packs, so when he's had a long day at seminar, etc, he can cool off any potential inflammation).