Nodebox looks awesome, indeed. By the way, Ricardo Lafuente is working on Shoebox, a rewrite of Nodebox that works on Linux using the Cairo backend. http://shoebox.sollec.org/

In fact, it seems the examples I based my code on are from this site (in my “circles.inx” you still see traces of the “ekips” domain name — which I didn’t change).

Technically, scriptographer and the extensions of inkscape are not the same thing. Scriptographer is a java programme that ‘talks’ to the Illustrator functionalities. If Illustrator has a function that, for example, fills a shape with a color, scriptographer can trigger this ‘fill’ function without having to re-implement it.
On the contrary, in Inkscape extensions, you have to write the functions yourself since the programme doesn’t answer to your script calls. It just passes the svg document to the script as input and tries to display it when the script has finished working on it. It is rather unfortunate since the most acrobatic parts of the inkscape code are difficult to re-implement. Therefore the pace of development of extensions may be a bit slower if you try to make ambitious things.

However in the newest versions of inkscape, the developers offer two additional ways to script. One is from the outside of inkscape and ressembles a ‘slave’ mode. The other is to use an embedded console that allows you to inject python or perl code when the programme is open. I haven’t investigated these yet, but it seems that these new developments give the possibility to ‘talk’ to inkscape’s most interesting functionalities.

To install this extension, I copied the files into /usr/share/inkscape/extensions and restarted Inkscape; after that a new menu-item ‘Python’ was added under ‘Effects’.