Minecraft DS by Smelaum, another homebrew project seeking to adapt Mojang’s indie PC game for a handheld.
While this 3D demo is impressive, it only has a few basic features: terrain generation, adding/removing blocks, and map streaming from the game file. Smealum says he is working on an actual level generator (what you see here is generated with test code) and support for saving.
As for LuaCraft, that 2D Minecraft-inspired homebrew we featured a while ago, it looks like that’s still under development but now under the name Lumikha. It’s a shame that there isn’t any 3DS homebrew, as both of these projects could benefit from that system’s extra power.
See also: More Nintendo DS homebrew