I got an idea about the nasty sticky point on magnet circuits (magnetodynamics sound better?).
Just build a circuit that enable an strong electromagnet just after steel ball reach strongest permanent magnet. You can use a hall switch for activate electromagnet in the right time and avoid unnecessary power consumption. After steel ball accelerate up to your electromagnet, you can turn off it and the ball will reach the weakest permanent magnet, and your cycle will continue.
If you are looking into getting more power from this kind of system for each cycle, you only need to extend the path that the steel ball travel (you will need more magnets).
And for the picking circuit (electricity generator circuit), you can experiment with coils attached to the travel path of the ball. 8)