Just wanted to inform you all that I've just released a new library called NControl for Xamarin Forms that helps you write custom controls without the need for custom renderers.
The library uses the NGraphics library to perform custom drawing, and allows for control containment to make it easy to build complex controls.
The sample project contains a few custom controls to demonstrate the library. A cross-platform implementation of a rounded corner control, a progress control and a custom button. Take a look at the source code to see some example usage of animations on Xamarin.Forms to make your user interface more alive.
The project has been released under the MIT license so open your IDE of choice and download the Nuget package and create some awesome controls!
A blog post has also been published about the library.
Enjoy :-)