The Google Translate feature in the dropdown list of features is just like any CMS content feature it can only be put in a content pane.
But the GoogleTranslatePanel can be used anywhere in layout.master. However the javascript and css from google can also affect how it renders. The GoogleTranslatePanel is just a convenience control, you could wire up the widget directly using html and javascript from google in layout.master, the control is just doing that for you but you may get more control doing it yourself. However styling and positioning it may involve working against the style that google is imposing on it from their css and javascript. You can google for "styling the google translate widet" for more info.
Hope that helps,
Joe