The rocky sales start of the 3DS is the reason why we're not ghostly grooving yet.
Two Natsume releases, Gabrielle's Ghostly Groove and Harvest Moon: Tale of Two Towns, were delayed due to the lackluster early sales of the 3DS, according to a Natsume representative.
Gabrielle's Ghostly Groove came out in Japan in July, and is ready to be released in North America. However, it was pushed back to an October release, primarily because of system sales, but also because of the game's Halloween-esque setting.
Additionally, Harvest Moon on 3DS, which is a North America exclusive, is coming out in October, a month after its DS counterpart.
Natsume has released one 3DS game in North America, Reel Fishing Paradise 3D, to date.