Back to normal after wiping data and clean flashing. Thanks to Titanium Backup it wasn't much trouble. The mirror enabler must have been the culprit. I'd really wanted to check that out but shortly after installing was when wifi vanished.
Sent from my Galaxy Nexus using Tapatalk
The mirror enabler seems to randomly cause this to happen for me too. I've found a way to fix it: Turn on the wireless hotspot feature, then turn it off again. For me, this does something that seems to reset the wifi driver so that it starts working normally again. Hope this helps others with the same issue.