Single rays can be shot, where and what you do with them is mostly up to you.
On the left the Context node delivers all current render/shading context data, the Ray node in the middle tells you what kind of ray is currently being processed. On the right side is the Trace Ray node that allows you to cast an own ray.
I don't know what kind of sampling scenarios you have in mind. Additonaly to the Trace Ray node you also have Ambient Occlusion for sampling
If i remember correctly there were examples for rounded edge shaders build by testers, however due to licensing restrictions we can't provide any of these.
Current sampling methods only work for surfaces, not volumes, however you can do some effects that take object thickness into account by casting rays inside of them. This is not a SSS replacement though but might be good for some interesting effects. I used this for X-Ray effects and similar.
I think you will be able to tell if this is interesting for you or not, once the Demo becomes available.