Xamarin Studio's Designer for iOS will allow you to create storyboards graphically, and do so more easily than using Xcode because it's streamlined for this specific purpose. Although you cannot create individual XIB files using the Xamarin Studio designer, you do not necessarily need to if your iOS application will be built entirely on storyboards. You can open the Designer either by double-clicking an existing STORYBOARD file, or right-clicking on a STORYBOARD file and navigating to Open With | iOS Designer.

As you can see in the following screenshot, the designer for the iOS interface is made up of five components:

The design surface is your canvas to create new user interfaces, and it will open in the editor area of Xamarin Studio when you open a STORYBOARD file. The Toolbox pane shows the controls and objects you can drag-and-drop onto the design surface. The Properties box displays information about the currently selected object, such as identity, look...