Well, I went ahead and downloaded Mono For Android and the Windows Phone/XBox360 .Net SDK... and I have good news.
Scripter2 works right out of the box with Mono For Android. And it works with very minimal modifications when compiled for the XBox.(just had to reimplement
ApplicationException and change a minor method call to use an array)
So, if you're looking for a scripting engine to run on those devices where regular .Net dynamic languages don't work, I have your (I think) only option.
I will probably be doing more testing with XBox and Mono For Android in the near future. My only worries are memory usage. I know performance won't be the best, but I already know some places to start improving performance, and I'll be profiling it a lot more in the future.