Imagine writing code like this and having it build to native apps on both platforms:
I think Xamarin are going to be a really interesting company to watch for this stuff. Right now they have MonoTouch and MonoDroid as entirely separate products, allowing you to make apps using C#. But you can already reference libraries across both, and just do the UI plumbing separately, and if they're smart they will work very hard on what the author is describing.