The Japanese situation is similar to when they originally bought F-15, or rather built them under license. They were looking for a similar deal with F-35, without being involved in the development phase (or perhaps I should say 'development activity' due to concurrency). While that worked with F-15, the restrictions on certain F-35 technologies mean that they will have to by some sections fully assembled.
I think the Japan sale will be an interesting one to watch as it could well have an influence on other countries in the region that are potential F-35 customers, but all of of whom are currently uncommitted/undecided to some degree or other.