I have a tinkered with the shader, bssrdf sss, and have got some nice results with it. It took about half hour or so to figure it properly, well to my ability right now. As always not enough documentation with this sort of thing unless you down load the Sigraph paper and study pye and algorythms, mmm? Thought not , same here. Anyway thecatch with the paper is they only use a two colored skin map ie; pinkish skin and ruby red lips ( a bit of contrast) so you can use the default setting straight away. Great!!
But if you want your own results with your own skin maps its a different kettle of fish altogether. Check out the attached setting I used with a map and a bump map to get going. The setting on the scatter length is actually RGB settings. Now I come from a photo printing background and understand what colors make when you add more blue and red you get magenta and Green and blue make cyan and so forth, so I figured how to darken the shader without getting too complicated. Basically think Photoshop RGB kind of thing 0-255 so 0 is black and 255 is white and it be a bit clearer. Anyway I attached a grab and render from what I got in half hour hope it helps you out. Make sure your lights have ray tracing on and Sub surface Scatter in the attribute editor is turned on, ( its next to emit specular check box) Also be warned I have found there are issues with anything that is Alpha Mapped for use on transparent edges as well, Oh and when rendering, be a bit more patient than usual.
Regards to all