Hope this can be useful to someone else. I've made a new MonoTouch port of the OxyPlot 2D C# plot library, this one supporting both Pan & Pinch-Zoom gestures. I've also added iPad support, autolayout and added UTF8 font support. Now we can use a native C# plot library for MonoTouch in alternative to the C based CorePlot.
You can download it under the MIT Licence here: