I just ordered a pair of Japanese flats from Japan and received them today. Your going to end up spending close to 200 dollars with shipping but if you have wide feet and are disenchanted by the ridiculous moon shoe minimalist footwear the US market offers...
That is the portal to access different merchants who sell flats. Once you've found what you've wanted you'll have to set up a forwarding address with Tenso.com which will forward the package to your US address.
I don't speak Japanese but the process was fairly painless. The service was reliable and the merchant was in contact with me through every step of the process. You'll have to rely on Google translate quite a bit and if that doesn't help you to understand you can post the e-mail you need help translating to Yahoo! answers and someone will help you out. I was lucky to have some of my questions answered by an American who lived in Japan who also uses Rakuten.