I have my own technique which I think really maxes out shadow recovery from raw files. I have been using this for years since my digital rebel days, although I'm sure some of you have better/more efficient methods. This usually takes 20min or so of work and involves creating 3 different exposures from the raw and applying noise reduction to the mid and over exposed files. Then you stitch the 3 exposures together using hdr software or photoshop. Then I'll usually blend that in with the original file.
Anyway I rarely do this because it's work intensive but I was curious about the 5D III after reading this. Here are my results:
Original raw, saved as full sized tiff, resized and converted to jpg in photoshop. Not edited at all:
shadow recovery technique applied:
There is some loss of detail in the ferns but not bad considering the shadows were basically entirely black in the original shot. This technique works well; In the past I've even been able to extract some pretty crazy shadows from the rebel at 1600 ISO and clean it up. Even when shadow recovery is not needed, I've found this method to be useful for noise reduction while maintaining detail.
What's disappointing about all this is it proves beyond doubt that the data is there - it can be used but it seems the current photo processing software still is unable to give us a slider of some sort that will do all this automatically. I'll probably write up a detailed how-to on this soon for anyone interested. In the meantime I'll keep using this method and I'm glad to know the 5d III has this kind of DR, not that I was gonna use it anyway. Because let's be honest, if you need more dr than this you probably kind of suck at taking pictures.