Is there any "Show Brush On Surface" option in sculpt mode? I found this in the threads from GSoC 2010 or 2011, but can't find it now in blender. Is there an option somewhere or an addon that project brush circle on top of the surface of your model?
Sadly this isn't currently possible in blender, I believe that for one of many reasons it wasn't included into blender, that happens with GSoC projects quite often, sadly. (Maybe why blender didn't get any projects this year, 2015). As a result this isn't possible.