I am contracting as Xamarin Developer now developing with Xamarin.Forms. In my previous contract I developed an app which can be seen in App Store and Play Store. The app name is 'CarFinance247'. This app was developed natively for iOS and Android using Xamarin. And I have many other B2B apps developed with Xamarin in my 3 years of experience working for 4 different companies and my own projects.
I have good architectural skills knowing plenty of design patterns like Inversion of Control, Dependency Injection, Commands, Property Change, Factory for plugin in any database without changing a line of code (so the app will work fine with SQLite or MongoDb). I also know a lot of frameworks, complex like MVVMCross or easy to pick up for other developers if you plan to continue the project later with a different team not very skilled in Xamarin, I can use FreshMVVM for Xamarin.Forms.
I can suggest the best option for your project and the architecture for free and then you decide if I am good enough to build it or not.