So, as people whom are smart to do research know, Microsoft owns all the rights to Minecraft's console ports. Seeing as the iPod, iPhone, android, and Xperia play are all phones, they don't fall into that category. However, somehow the 3DS does seeing as it is a handheld CONSOLE. Also, even if it were to be released, look at the 3ds. How would you move Steve or whoever around? How would you look up and down? The circle pad? How would you move steve? The D-PAD? HOW UNCOMFORTABLE WOULD THAT BE!? You'd, like have your thumb on the DPAD, index finger on the CirclePad, and your Flipper on the L button. The other side would be simple. Now, take the XBOX controller. LeftTrigger for placing, Righttrigger for mining, X and Y for Crafting and Inventory, A for jumping, B for Throwing, right analog stick for moving, plus double tapping for sprint, left analog stick for looking. The DPAD could be used in the inventory and for some fly controls in creative.
In the longrun, the 3DS doesn't have enough buttons. Maybe with the circle pad pro?

Possibilites - Movement of head with stylus + control inventory.
Circle pad pro for movement of head.
Also label it as a pocket edition.