Smart String is amazing in it's ability to be compltelty independently addressed per node.
This means one node can be doing something say being on white while the node next to it is blue.
So the as long as you set up the animation of the chase effect you described in Vixen or LSP there is no limit to what you can do.
Here is a video of some of the effects Smart String can do You are not allowed to view links.
Register or
Loginand this video is RJ explaining the way to animate the lights and how they are set up You are not allowed to view links.
Register or
LoginAgain the only limitation is as Paul said the amount of time you want to devote to setting up the animation.
- James