Drop Down Menu similar to Amazon's Big Menu

I am looking for a drop down menu (plugin?) that is similar to the menu on Amazon that you find under ‘Shop by Department’.

It is a drop down-menu where the second level child pages are in a fixed kind of window.

––——-– Menu –––––——–––—————————–
| 1stChild 1 | Second-level-child 2.1 |
| 1stChild 2 | Second-level-child 2.2 |
| 1stChild 3 | Second-level-child 2.3 |
| 1stChild 4 | Second-level-child 2.4 |
———————————-

So no matter which 1stChild menu item is chosen, the Second-level-children are still shown in the same place.

Ben Kamens developed a jQuery plugin. The description of which can be found here. Here is a working example and it is very close to what I have in mind.

I would be happy if I could find a plugin that makes this possible! Does anyone know a way to get there?

Thanks!