Mudbox has such a feature to bend curves right over the mesh.
The nice thing is they rest on the body, rotate with the view and you can brush along them!
Sculpting curve strokes only project the curve onto the surface. I don’t believe you can currently convert grease pencil surface strokes to sculpt strokes
I remember seeing a tutorial about that, forgot where (I’m trying to recall);
maybe Craig Jones is the right person to answer.
paolo
A couple of versions ago, Psy-Fi added his curve/line tool for both painting and sculpting modes , for now i only have error 500 from their server but it’s explained there :
http://wiki.blender.org/index.php/Dev:Ref/Release_Notes/2.72/Painting
You can then easily create curve (hold CTRL+click to add curve points) and draw/stroke on your models with them, it works very nice
