Katsuhito Ishii's 2004 The Taste of Tea has been given a Japan-only special edition box set that I was able to acquire recently. If you can get a hold of one it is a beautifully done set and has some physical extras that are well worth the trouble to track one down.
The main disc is the regular edition you can get separately of the film and its accompanying disc of special features - mainly a 90 minute featurette and a handful of other videos adding up to two and a half hours of material on the second disc. Unfortunately none of it being English subtitled. A highlight of the disc is a video of the mother's animation except with an actual soundtrack. Also in this set is a bonus disc packaged separately entitled "A Story of Color and Shape" (茶の味：色と形のはなし). It is a 151 minute making-of documentary and unlike the main disc with the feature film this does not include English subtitles. The quality is not great as it is more of a collection of video diaries shot digitally of the many aspects of the film's production. We see everything from the animation work on the film (the grandfather's and the mother's) as well as costume design. There is quite a bit here and I don't think the lack of English subs would hinder all of that could be taken from the doc for a fan.
What makes this set an absolute must have for any fan of the movie are the replicas of the four animated-portrait journals that Grandfather made. They are lovingly reproduced on a thick paper stock can easily be flipped through to watch the charcoal episodes come to life.