Some other ideas:
If you have MoGraph you can use a Cloner along with an Inheritance Effector (to move the stack) and a Step Effector (to create a delay effect). Add in a Delay Effector set to spring mode and you can get a pretty cool effect.
If you have R10 you can use the delay function of the new Constraint Tag.
If you have Mocca you can use a soft IK chain.