The W3C Japanese Layout Task Force (JLTF) has a working draft of “Requirements of Japanese Text Layout” available at http://www.w3.org/TR/2008/WD-jlreq-20081015/.
It is an impressive body of work that the JLTF has been working on for a while. This is the current iteration of the document for which I went to a meeting in Tokyo last September, and I went to the W3C Technical Plenary in Mandelieu this week specifically for the JLTF meeting reviewing the working draft.
The task force is looking for feedback (to www-i18n-comments@w3.org) by 15 November 2008.