Definitely an interesting concept. I'd be interested. I do have to wonder though if Android users will have any reason to use WP, and a lot of WP users probably wouldn't use Android.
Is this simply a scheme by Microsoft to inflate market share numbers? Think about it; a lot of Android users are also buying a WP, whether or not they care or even know it, or ever use it. Microsoft can report it as a WP sale which raises numbers even if it's never used. 5 million HTC One's were sold in the first 2 months after it was released in March 2013. If they all would've had WP8 installed it would've increased WP sales by at least 50%, judging by my rough estimation.