Steve Blackmon of the BlurBeta team has announced that their RayFX Ink/Paint material would be available yesterday late or this wednesday.
Keep an eye on their RayFX Public beta webpage, and check out a teaser image in the mean time.
What is RayFX Ink/Paint ?
RayFX Ink/Paint is a cel shader effect.
Some of the features include automatic and lighting/texture map based line width generation, object intersection support and resolution independent line widths.