I'm trying to share as much code between my common UIViews as possible by subclassing UIView.
Is there a way to make this UIView accessable in Interface Builder?
What's the best way to reuse hand-coded UIViews in Cocoa?
Add a normal UIView to your window/view in interface builder and in the Identity Inspector, change the name of the class to your UIView subclass.
If you want to make your custom views available in interface builder permanently, you could create a plugin for interface builder.
See here: How do you display custom UIViews in InterfaceBuilder?