Ever since I switch to Safari as my main browser from Firefox/Chome, the one thing I have missed is the awesome/omnibar.
Well, no longer!
Safari Omnibar is a bundle that adds the omnibar functionality to Safari (including disabling the separate search field in the toolbar). You can add your own search providers and the only thing is seems to be missing for the moment is injection of live search suggestions (which is said to be coming).
Go ahead and give it a try. I’m enjoying it with DuckDuckGo at the moment.