What an excellent gift! I'm sure he'll enjoy it.

If you want to get him some accessories I would recommend these containers: http://www.amazon.com/Soy-Sauce-Container--15-Bag/dp/B001AJ8HOG/ref=sr_1_21?ie=UTF8&qid=1354536165&sr=8-21&keywords=bento . It says their soy sauce containers but I mainly use them for salad dressing.

Also: http://www.amazon.com/Kitchen-Supply-2373-8-Inch-Silicone/dp/B001ET7B9Y/ref=wl_it_dp_o_pC_nS_nC?ie=UTF8&colid=2SFPTJX5AEURZ&coliid=I1XJ06TU3R7KY9

The silicone baking cups help keep things separate in the bento box until you're ready to mix them. Like so.