Cool idea. Maybe you could hire me! I'm cuban but I don't think that most japanese, or people in general for that matter, would be able to tell the difference. I could lend an air of authenticity to the enterprise :D

I went to one in Osaka about 10 years ago. It was o.k. If you want any ethnic food restaurant to work in Japan, just take out all the flavor, substitute japanese ingredients, change all the names of the food to fit the japanese idea of what the food should be called. Then say, "japan is an interunationaru contori," about 10,000 times. Throw some phony south american decorations (rather than mexican) on the wall. Make sure the place is fun for 20-something-year-old-girls by playing vapid pop-music on the stereo. Then the place will be a hit.