I put this also on blenderstorm, but wish to get also some feedback here
Now we have the great tool “shrinkwrap” that allows us to retopo and keep the precision sculpting.
But we cannot yet get back the texture/mesh colors from the previous mesh to the new one.
That would not be too difficult to implement, is it?
E.g. using shrinkwrap, when the mesh goes to “the closest surface point”, can we associate to it also the vertex color of that point
Have you tried texture baking from the hi-res object to the retopo one?
You got my point ; but I don’t think it is possible to do that.
The topology of the starting mesh has not much (even nothing) to do with the one after retopo (that’s kind of the point of retopo)
Hence the 2 meshes have “no connection”/“nothing in common” other that the new one is sticking on the first one.
Ben63 -This sounds like what you’re looking for:
http://www.blender.org/development/release-logs/blender-246/render-baking/
Just select your highrez mesh, shift select your low rez mesh and bake with “selected to active” turned on.
WoW! I didn’t know we have that 
That fits perfectly with my needs (and I am lucky, it’s kind of recent feature) Thanks guys!