Well, I have a couple of ideas, if you want to do something like that.
1. Japanese Futon
I've heard that they're fairly comfortable, and can be folded up and put in the closet during the day. That would be ideal for people who live in a small space, like me. My bed blocks outlets and is always getting in the way in my room. There's not really room to walk around or do projects in there. I had thought of getting a bedroll or a cot, but this might be better.
2. Tools for making/serving Sushi
I've occasionally thought about cooking Sushi at home, rather than going out to eat. I can find the ingredients easily enough, but the hard part is finding the stuff used to cook/prepare them the way they do in Japan.
3. Sake
That would depend on your ability to verify the age of the purchaser, of course. But if you have any way to verify that someone is over 21, then I think a lot of people would be interested in buying real Japanese Sake. Americans love everything from Russian Vodka to French Champagne, so why not?
4. Calligraphy brushes
For people learning how to draw Japanese and Chinese characters, I think drawing them with a brush might help in understanding the concept of stroke order and getting a "feel" for the characters. Drawing them with a pen makes mistakes easier, and you get no sense of why you'd draw it in a certain way. If you draw the characters with a paintbrush, the original idea behind the shape of the characters becomes a lot clearer, and this might help in learning the language.
5. Japanese fans
I think the Japanese have some of the best paper fans for when there's a power outage and/or going outdoors in the summer. I can imagine a line of the fans with JREF advertising on them. That way, when people are outside fanning themselves in the summer, other people will take notice, and possibly come here to buy things or become members.
Not sure if these seem like good ideas or not, but it's definitely something different from anime that people might be interested in.
