Stardock vs Apple - a multi-billion dollar company? I think they would ignore any cease and desist letters. Stardock would probably need to get attorneys involved.
Correct me if I'm wrong but as for the dock itself - didn't Apple come out with the first one?
First, my post was entirely tongue-in-cheek. Second, it is the "Stacks" feature of the Leopard dock that is the target of my jest - ObjectDock had that feature long before Leopard.
As for docks in general, I believe Excalpius is exactly correct.