Maki's announcement of her upcoming bento cookbook make me realize we've been using a copy of "Japanese Cooking for Health and Fitness" for almost 20 years. My husband bought this book in the 80's, long before we met and its been a food stained staple in our kitchen ever since. Its still in print and the easy recipes don't require hard to find ingreidents; the book was published in 1983, back when Japanese food was still considered to be pretty exotic. In addition to recipes the book has photos of Japanese items as they appear packaged in stores, which is really helpful if you're shopping for something you've never bought before.
Every recipe has a phtoto of the finished dish and many of them are bento friendly. Here is the link to US Amazon, the publisher is Barron's so it should be available all over the world.