While trying to change the location of a chest via command block by editing the x, y, and z data tags through the /blockdata command, it says that the block was indeed updated, but does not show any change in the tags or to the chest. It is highly likely the command was not intended to be used like this, but while using /blockdata ~ ~-1 ~ {} I noticed it was indeed an option and expected it to work. Even if it was not intended to be used like this, when I saw this I didn't expect it to work, but wished it would as the functionality would be a great asset to my adventure map.