Some brainstorm regarding this voxel idea. You can actually achieve similar effects in FC. First, you need to obtain the Path wires. Basically, just grab the Edges from the Path object's Shape property. You probably need to sort it manually, by playing around with Path.sortWires(). Then checkout how Draft.PathArray generates an array of shapes along a given wire. The code is in Draft.py, class _PathArray. I'd recommend using a simple Cube, which may be the fastest primitive for rendering. You can't really use PathArray directly, because FC is not designed to handle large amount of objects. You CAN directly use Coin3D rendering to duplicate the cube Coin node along the path. If you are not familiar with Coin3D, take a quick look at FC wiki here.
Okay, so if you mange to pull the stunt, and make the above working, you will be getting a large amount of cubes in milling order. If the cubes are small enough, it may actually look nice from a distant (hint, use 'Shaded' display mode). Then simulation is just a matter of hiding/showing those cubes in forward/reversed order.