This is cool, although I'd rather have a nice voxel editor that I can use to print stuff to a Makerbot. Would I be best served just using a Minecraft map editor, even though I don't play Minecraft?
You should try out: http://3dtin.com for a MineCraft experience, or you can use http://tinkercad.com for a more CAD-like design. Both pretty cool and export STLs needed for manufacturing in 3D.