Ran across a tutorial a while back thats been a big help on creating items with regular repeating rotations or shifts.
<Pardon I don't have the tutorial handy but here's the gist using stairs.>
First make one stair tread, and then in the animation section define how that one tread moves. Grand sweeping stairs, spirals, something more M.C. Escher, whatever. When you run the animation sequence there is a option to leave a copy of the model at each key frame position. Running the movement animation on a single tread takes a few seconds, and there you go stairs without all the fiddly editing. If you want to edit the fine details you just undo the group structure and have at it.
Guild of Writers
