Here is some examples of retouching from my own work.
Here is a photoshop reel of some masking/compositing I have done for Kevin Cruff Photography.
Here are some images I have worked on with Nick Hall Photography. Unfortunately I don't have before and afters, but these images were composited from images of a sky, the talent image, and some panoramas from a landscape. I created the background plates with several images of a landscape, masked out the talent, created skys from several plates to create large panoramas and composited them all together with some color work to make it look like it all blends. Often Nick would finish the final touches on the images, since I was just a retouching intern.
For this image below I built the sky, the can fields was a seperate image i had to mask out and so was the volcano and composited them all together with some color work.