Inkscape 0.44 - Faster, Bigger, Better
wrong wrong WRONG!
SVG does support CMYK
Actually, at the moment SVG doesn't support CMYK. However it is proposed that it will at some point. What you cited there was the proposed draft requirements from over four years ago. I think they might be getting close to finally putting 1.2 out, but even in the last rounds of finalizing SVG 1.1 they dropped things, so one mustn't count one's chickens before they're hatched.
In fact, back in April of 2005 they pulled back their draft 1.2 spec and replaced it with a simple placeholder stating that things were in flux. So we're all now just sitting, waiting with baited breath.