Spotlight in upper right screen corner in Mountain Lion
It used to be the realm of the first menu-bar item to start the got the prized first (last?) slot in the menu bar.  But since Spotlight, it's always had the prime location to itself.  Now it's been usurped.  That's not to say that some command line hack won't turn up that can change things, but as things stand there is no officially supported/provided way of doing this via a preference pane.

But I wouldn't actually go looking - the whole point of the spotlight button is to allow you to type in some search criteria.  As such, why click the icon, then move to the keyboard - just use the provided keyboard shortcut instead - command+space is not only the easiest to remember (for me) it's also the easiest to pull off even if you are terrible at remembering shortcuts.  I use it as my command launcher these days, just command+space+"sa"+return starts Safari up faster than mousework for me.