Nintendo have confirmed that Kingdom Hearts 3D [Dream Drop Distance] will receive a digital release on Nintendo 3DS' eShop. This confirmation comes from Joystiq, who heard the news from Nintendo in a E3 investor presentation. A list of titles confirmed for a digital release can be seen below.
Update: Joystiq have added that Nintendo have included an update to the announcement. Apparently, the digital release announcement "refers to first-party titles only". As Kingdom Hearts 3D is not a first-party title, it seems they were mistaken in announcing that Kingdom Hearts 3D receive a digital release.