I did some testing of a rock surface in ZBrush, but somehow got stuff messed up, like the UV maps. In other attempts when sculpting using spotlight, the depth didn't happen according to the lights/darks in the texture imported. I need to see more tuts, I suppose.
Anyway, here's some attempts, maybe of small use.
EDIT: the other tgo is just over 5000MB, so I can't post it.