Yesterday there was a question on StackOverflow about PRISM....
Although actually it wasn't really about PRISM - instead it was more about 'Could MvvmCross be used in WPF?' and 'Could MvvmCross support more complicated Composite UIs?'
I was pretty sure MvvmCross could - especially given our PCL base and our presenter-based Show mechanisms.
So I set about providing it....
And a few hours later - I've checked in some code :)
More details in the answer: http://stackoverflow.com/questions/13863152/mvvmcross-and-prism-combination/13864564#13864564
And a video of it in action: