snivens: well, I have some ideas on my mind. If you don't need completely dynamic solutions, there's been some stuff floating around for ages. Apart from that, if you use the export to OBJ dialog in Qubicle you can choose to make one model per cube, then remove the cubes one by one programatically. Or if you want something like Cube World or Voxatron, you can use Unite importer for regular in-game model and then OBJ export a death-animation model. Once the monster, or whatever it is you're having, dies, you'll just replace the model and assign each voxel different collision class and some physics attributes on instance creation. If you want some cool voxel particles, you'll just use little cubes and paint them.
If you want semi-dynamic destruction for terrain for example, you can have another mesh that looks like a voxel hole and then just use mesh morphing to achieve the desired effect. Don't know how Unity would handle it, I think it does support geometry shaders though. Would require further research.