Here is the first draft of a Dbus based Inkscape scripting API:
http://www.cs.grinnell.edu/~bergsore/inkscapeDbusRef.html (Many thanks to the ConsoleKit team for the scripts and build system I used to generate this documentation.)
I would welcome any comments or criticisms, the interface is very much still up in the air so any suggestions, from small changes to major issues, would be welcome.
I would particularly like to hear if people think that this would potentially support the ways in which they use Inkscape, or whether there are use cases this doesn't address. If there are lots of uses that this interface does not support, additional interfaces geared towards different users could be added. (In fact there was originally one more interface than there is now, see document_new() for details.)
If you like the current API (in general) feel free to suggest additional functions or functionality.
Finally, how would you like to see this extended? Dbus has proven to be quite responsive and robust for this application. How would you build off the basic platform of the Inkscape application interface?
I will keep the posted link updated as I make changes based on peoples feedback.
-Soren