Is it possible to add the close/minimize/maximize bar to the top GNOME bar like in Unity so it takes up less space? I'm running Gnome 3.x in Ubuntu.
Did you check the gnome3 plugin site?
In gnome 3.10 the new behavior is that maximized apps lost the titlebar in a similar way to unity if that helps. For now only the core applications behave like this and neither have a tittlebar since the close button is in the toolbar.
Hopefully Ubuntu 14.04 will get gnome 3.10.