The last line (the super-smooth one) was done using a large number of small replicator points. Remember, it's like you're drawing a line using Legos: to make the line smoother, you need to use smaller Legos and a lot more of 'em. The source image for the replicator was the same small rectangle, only I scaled it down in X until it was taller than wide, and then cranked up the number of points. To smooth out the drawing (a more fade-in look), increase the Spread in the Sequence Replicator behavior.
The tighter the turns in your line, the more points you need to keep it smooth, but if your line is fairly straight, you won't need as many points. Just keep in mind that the more points you use, the slower things will go, so play with it until it's just right.
As for the shading, I just used the replicator controls to colorize it with a gradient.