I just did some routine updates through the Update Manager, and upon the requested reboot, both the unity panel and bar are gone. Desktop notifications are still there, though the rendering seems broken, and it's black opaque where the alpha should be. Luckily I can still run a web browser since I had a Firefox shortcut on my desktop.
I have tried—
Checking CCSM to make sure the Unity Plugin was turned on — It was.
unity --resetin the terminal — It said the reset function was "deprecated".