Recently Andrei - opcode - has taken the same resx files and pushed them in a different direction.
He looked at the existing Json code and he didn't like it... As he said, "I went through the N+1 video and tried to understand localization using the Json localization plugin but it almost made me cry"... so instead of crying he went off and created an alternative implementation - using resx files directly from ViewModels to allow i18n text bindings like:
android:layout_width="wrap_content" android:layout_height="wrap_content" />
This alternative option is awesome. It fits exactly with one of the fundamental principles of MvvmCross - that people should write the code they want to write - the app is the king!
If you want to learn more about this approach then the blog post and code is at: http://enginecore.blogspot.co.uk/2013/09/localization-in-xamarin-mvvmcross_18.html