I think that when you want to sculpt organic shapes (like in your case i presume), mesh are not ideal. I'm currently playing around with voxels (3d pixels) instead and although at first one would loose his bearings due to the lack of reference points, it's pretty cool once you get used to it and there so many things you can do with voxels you cannot do with usual CAD systems.

Try 3dcoat, from http://3d-coat.com/3d-coat-45/

They have a free trial fully functional version,

and lot's of great tutorials here:
https://www.youtube.com/user/PILGWAY3DCoat/videos

I import my scans and sculpt around them, really enjoyable.