Thank you, Simon, for trying to clarify.
But the situation is a different one: Both Illustrator and Inkscape are written in C / C++. For creating Scriptographer, I had to write a C plugin that hooks into Adobe's Plugin API and then invokes a JVM within which I use a Java class hierarchy for representing Adobe's SDK in a cleaner and more object oriented way than they did. These classes are linked to Adobe's C API through JNI. They are then simplified through Java - Rino Wrappers to make them easy to use in JavaScript through Rhino.
It's all very complicated, but not in the way you were explaining. The problem with porting this to Inkscape is the fact that Scriptographer is tightly bound to Illustrator. I did not have a look at Inkscape's Plugin API (I assume there is one), but I doubt that they are similar. Developing a Scriptographer for Inkscape would probably be even more work than it took to do the version for Illustrator, as I would need to simulate the behavior in Illustrator.
Therefore I don't think I'll be able to cover Inkscape, I'm afraid.