Maybe it would be more accurate to say Thumbelina is a Danish Princess Kaguya since the Japanese fairy tale predates Andersen's by... a VERY long time!
Do you remember THIS POST from waaaaaay back in 2009 about Japan's oldest fairy tale, "The Tale of the Bamboo Cutter", coming to us soon from Studio Ghibli? Well, we're (finally!) getting close!
From MoviePilot (older info, so the title has changed):
Grave of the Fireflies director adapts the oldest Japanese fairy taleThe legend of princess Kaguya - a pocket-sized baby who was discovered by an old bamboo cutter named Taketori no Okina, while growing inside the stalk of a glowing bamboo plant. With Tale Of The Bamboo Cutter, Isao Takahata is creating his interpretation of the oldest surviving work of fiction in the Japanese language Tale Of The Bamboo Cutter. The story is said to have existed since the 9th or 10th century, and is known by virtually every Japanese child on Earth.
The film is directed by Studio Ghibli’s co-founder Isao Takahata of fame. [Edit FTNH: the same studio that brought us other fairy tale films such as Ponyo, Howl's Moving Castle, Spirited Away, My Neighbor Totoro ] (“The Tale of Princess Kaguya”) is a retelling of an old Japanese folk story, “The Tale of the Bamboo Cutter”, in which a princess discovers a baby in a bamboo plant. In the film, a baby girl, Kaguya-hime, the size of a thumb is discovered asleep in a glowing bamboo stalk. The film is set to the style of traditional Japanese picture scrolls.[FTNH edit: I added a link to the information available on Wikipedia in the above statement if you're interested in the (sparse) details. There are a couple of additions to information such as Producers and the film score HERE as well.]
Although there isn't much to look at yet, we do have a poster! (See top of post.) Interestingly, the tag line apparently reads: "A princess' crime and punishment." That may be confusing to people who intimately acquainted with the tale, like the Japanese are, but it does make sense.
The film was going to be co-released this Summer with Studio Ghibli's other film du jour, The Wind Rises (directed by Miyazaki) but due to some internal story-hiccups Princess Kaguya won't be released now until Fall*. With The Wind Rises still on target for release in July (in Japan), there's a chance we'll be treated to a teaser for Ghibli's new/old fairy tale around the same time. (We can hope!)
The Tale of Princess Kaguya is reportedly in post-production (though how that can be when they were still changing story boards in February, I don't know! Must have an amazing set of very hard working animators!) and last available information still confirms a plan to release in Autumn 2013, but it's still difficult to find out much else about it at this point.
I'll keep my FT news hound nose to the Ghibli wind for you!
*(Quoted from the Ghibli blog) The Japanese film distribution company Toho said Kaguya Hime no Monogatari needed to be pushed back in order to give Studio Ghibli to enough time to make it the best it can be. Toho added that The Tale of Princess Kaguya, which is based on the traditional Japanese folk tale The Tale of the Bamboo Cutter, needs more time than originally expected to work out the plot. While this has no effect on the movies’ release dates for outside of Japan, which haven’t even been announced yet, its sure to disappoint domestic Studio Ghibli fans just a touch.