Useful third-party Object-C GUI add-ons for iPhone development

When I develop in .NET there's lots of UI controls from companies like Infragistics and Telerik that enable me to build above-and-beyond standard usability and stylish GUIs rapidly. Is there anything like that for iPhone Objective-C de开发者_如何学运维velopment?

There's the venerable and lauded three20 library, but some might be concerned about use of private frameworks, which will get your app rejected.

May become useful for you as well. TouchCustoms There is more inside that described. Never had a good chance to write documentation for every small detail.