Whilst we have been working on various mobile solutions we have made extensive use of open source libraries, in particular MvvmCross.
MvvmCross has been in development for a number of years and is used to underpin some very high profile commercial Xamarin based mobile applications. The primary focus of the library is to bring a unified WPF-like data binding approach to all available mobile and desktop platforms. Being able to use a design pattern such as Mvvm on platforms like iOS hugely increases developer productivity and application unit testing. We highly recommend this framework.
Over the past few months we have made a number of code contributions back into this excellent framework. Currently our main contribution has been in creating the MvvmCross iOS Support library to aid fellow developers developing for the Apple platform.
Let us know what you think!