By using Mono for Android developed by Xamarin, I have been able to build the entire csunits class library, and as a proof-of-concept that the library is indeed usable on the Android platform I have created a tiny unit converter application (similar to the Silverlight and Windows Phone applications I have developed earlier).
Here is what the unit converter application looks like in an Android emulator:
So far I have only tested the functionality in an Android emulator. Deployment on a real phone or tablet device is not for free.
I did experience several caveats when developing. The most notable problem was that the mandatory signing of the application package did not work correctly when Java 7 was installed on the computer (mentioned in a byline here, for example). It took some time before I could figure out that this was the reason my Mono for Android applications were never deployed on the emulator...
Mono for Android is of course lagging behind the main (Java) Android. As far as my initial attempts have revealed, the Mono Android API is not entirely complete vis-à-vis the corresponding Java Android API. The Android Honeycomb API for tablets is also not yet available on Mono for Android. It would otherwise be interesting to see if the C# DICOM class library mdcm could be built for use on Android as well?
There is also the concern that Xamarin is simultaneously developing Monotouch for iOS devices (iPhone and iPad). Android and iOS might just be one platform too many to maintain for Xamarin?
By the way, csunits on Monotouch remains to be tested. Given the success with Mono for Android, csunits and Monotouch should be no issue at all. Current lack of development resources (read: a Mac computer) prevents me from testing this right away. Who knows, maybe there is someone else out there who would like to give it a try?