[Inkscape-user] Automatically set Z-order

Is there a way in Inkscape (extension/plugin) to automatically set the z-order of a number of objects?

For example, I want to do what is shown by this image: http://www.maj.com/gallery/ffaat/Stuff/howto.png

(The objects here are the same just for convenience. They are not necessarily the same, and are not necessarily in a grid).

Ideally, I could provide a direction/line and have it change the z-order of all the selected objects in that orientation (though I would settle for top->down and left->right as I could just pre- and post- rotate)

I have written script-fu extension for GIMP before, but think that Inkscape is much harder to add to that way...

-Rob A>