Hey ! I work on a SandBox multiplayer Game.
The game use the multiplayer plugin and for the moment you can find :
A lobby where you can join or create a room !
In game you have a inventory.
10 normal block.
3 electric block (you will be able in the future to make electric circuit).
And all of the movement and collision are client sided.
You can test the game here
:http://gamejolt.com/games/other/infinityvoxel-multiplayer-game/73969/