
full post and link for download the shader:
http://www.blenderartists.org/forum/sho ... -to-Cycles

and now it makes sense. because arnold doesn't have an official skin shader, he is copying a shader compound that andrea's bystrom started which was ported to cpp by the sitoa developer, stefano. also, andrea's was inspired by the mental ray skin shader...The skin shader in Arnold, however, is just an elaborate (and publically available) node group that I've emulated. While I've had to get creative in recreating some of the nodes that I take for granted in SoftImage with special groups, I haven't had to do any special coding to get things running, and I don't expect I will. Chalk that up to the great minds behind Blender's node system and Cycles itself.