Hmmm. There are music & video search tabs in my (12.04) dock that do seem to search out online. The music purchase links go to http://one.ubuntu.com though. The video searches seem to go to BBC iPlayer & YouTube.
Your settings tweaks don't work on 12.04 - any idea how I would go about disabling this?
(The settings schema "com.canonical.Unity.Lenses" doesn't exist on my system.)