I am trying to accomplish the same look of my UISearchBar with a TextField within it, as in my iOS 6 app. I have tried to code it in several ways and not yet been successful
Create a UIView *textFieldContainer with your target frame, add your textfield to that UIView and then add that textFieldContainer as a navigation item. i.e. your approach remains the same just the textfield comes inside a container and you play with that container.