Well, to the point :-) I made a small patch (and a small test-file), which I have used for the last month with a CVS-update almost every day (no crashes), and I would like to know if anyone is interested in them?
Of course! Any patches are welcome, but SVG compliance patches are doubly so. Please use the patch tracker.
I would like to look into a blend tool (and some other more or less useful tools), but since I'm new to the internals of Inkscape, I would like to know if it's sane in it's current state (with the structural changes going on).
On one hand, all structural changes so far have been pretty incremental and have not broken irreparably anything that worked before. So if you want to dive into it, now is as good as any other time. On the other hand, our plans for extensions and rearchitecturing are not yet set in stone, and you may influence what and when is being changed based on your requirements and ideas.
I could still try to make an abstract outline of the blend function, which then could be implemented later (when the Extension API has been implemented around version 0.42?).
I think Blend is a pretty basic functionality that deserves to be in the core rather than in a plugin or extension. If you really can controbute to that goal, even if only by planning, that would be very welcome.