TUAW has a “cautionary tale” of what happens when attempting to move or rename the “Mobile Documents” folder where iCloud documents are stored:
“As if it were a swarm of bees, you should stay away from the SyncServices folder.’ — Apple
The moral of the story that I am about to tell is that Apple’s advice about the SyncServices folder also applies to your iCloud documents. Here is the summary:
Do not move your iCloud folder. Do not touch your iCloud folder. Consider it the digital equivalent of a hand-grenade which has had the pin pulled and which is resting safely on its handle.”