I'm using Mono For Android (probably will use MonoTouch too soon) and MVVM-Cross to port of a Windows Store app (Work on progress by another team, in Parallel).
Unfortunately the Windows store app team started of without using MVVM-Cross. That lead to some Windows specific libraries (like Windows.ApplicationModel.Resources) being scattered across code that should be portable across other platforms (for eg "Windows.ApplicationModel.Resources.ResourceLoader" was used for localization).
I was wondering if there's a cross-platform alternative (or may be a mvvm-cross plugin) for some of these windows libraries. Or may be guidance on how to create my own plugin/alternative.
There is a resourceloader plugin which uses windows package content files and android asset files.
It is used in (for example) the customer management sample in order to load an XML data file - see https://github.com/slodge/MvvmCross-Tutorials/blob/master/Sample%20-%20CustomerManagement/CustomerManagement/CustomerManagement/Models/SimpleDataStore.cs
It's also used internally in the json i18n plugin.
If you want a different implementation on one platform, then you can override the plugin for just that platform.
If you want a different implementation on all platforms, then it should be easy to create your own plugin, or to inject implementation of an interface on each platform. See the explanation of mvvmcross IOC in Instantiation of ViewModels and Service classes