Been catching all the talks on X and Cairo that I can here. I definitely think we need to get started on getting cairo integrated into Inkscape. It turns out that Worth joined Red Hat, he moved to Wilsonville, which is only about 15 from me.
I don't know if I have time, but I'd love to experiment with adding cairo as an optional renderer, so people could compare it with the regular renderer. It sounds like performance issues are expected with cairo, so probably users would like being able to select between the two depending on if they need correctness or speed of use.
Rejon and I also attended the talk on liboil, a library for "optimization of inline loops", which is a collection of MMX / Assembler code for optimizing things such as graphics rendering, transformation math, etc. Rejon and I chatted with David Schleef, the liboil author, afterwards, and it sounds like it could be a great candidate for majorly improving cairo's performance.