For anyone that is interested, I have a PCL wrapper library around Xamarin.Mobile that will allow you to access the following services (below) in your PCL shared library. It can be found at: https://github.com/aritchie/acr-xamarin-forms and should be available on nuget sometime in the next few days.
- Camera
- Photo Gallery
- Geo-Location
All services are registered on Xamarin.Forms DependencyService.