If it's mostly menus that you're interested in - perhaps a decidedly low tech menu reader will do. The books are usually small - and fit into a purse or jacket pocket. One of my favorite series is the Al Ellison menu readers (now out of print but available from time to time on Ebay or Alibris - books available for French - Spanish - Italian - German - Mexican - Latin American - Swiss and Portuguese foods).

By the way - what if anything do you recommend for restaurants in Japan (I assume you've spent time there because you speak fluent Japanese)? My husband is learning Japanese for our trip - but I think his speaking will be a lot better than his reading by the time we get there). Robyn