I am having the same probplem with my toolbar, it one day decided to disappear, but when I drag it it doesnt show up! I've done this about 20 times.
I'm having the same problem. All of a sudden, there's just a grey space where the URL bar was. None of the various methods to restore it work. None of the keyboard shortcuts work to restore it.
There's a grey space in the 'customise tool bar' box where you are supposed to drag the option back to the toolbar. And there's no option in Preferences/Advanced to show it - half the Advanced menu has disappeared.
Very weird, and apparently irretrievable, since Safari for Mac is no longer available to download from Apple.
MacBook Pro 15" Core i7 2.6Ghz running 10.8.5.