I can create some simulation for oscillascope if you allow me to use the picture in your oscilloscope page.
I created a simple many years ago: [url=http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=34.0]Basic Function of an Oscilloscope[/url].
And a French version can be found at http://www.phy.ntnu.edu.tw/oldjava/cd-labo/oscillo/f_exper.htm
I hope the following is what you might want.
You can drag the magnet with mouse to other positions and click run again.
It will remember the last 5 traces.
Some of the position might not look right.
But I am using real gravitation formula to simulate it.
Actually, the magnet was simulated with the blue point near the center.
Attached image is the snapshot image created (Right Click select [u][b]Capture the screen[/b][/u] -> [u][b]Snapshot[/b][/u] ->[u][b]save[/b][/u] )
Because I only use one point and gravitation potential to simulate the magnet,
the model has it's limitation. You can use this to teach the limitation of physics model,too!
To really simulate a real magnet more complicate model need to be created
(dipole model will be more suitable for magnet but you want to teach about gravitation, so I use gravitation force in this simulation). I hope this is what you wanted.
Let me know what need to be improved.
[color=blue][b]The following is not an image but a java simulation (with image as background).[/b][/color]