I'm not sure how I managed to miss this, perhaps because it's still in 'developer preview', but a version of Android is officially available for the Raspberry Pi 3.
If you're really keen, you can download the image here for the developer preview 3.1.
Thanks to the recent release of Google's AIY Project with the latest version of the MagPi magazine (already selling for £40+ on ebay), the official guide for the project which is rumored to be on sale at a later date from Google, links to a github for running AIY Project on 'Android Things' with the aforementioned link to the developer preview.
Google also has an Android image with the AIY Project as opposed to it running on Raspbian.
It turns out there's a full site for Android Things and it runs on more than Raspberry Pi 3, it also runs on the intel Edison. However, it appears to be as 'bare bones' as the Windows 10 IoT Core, intended to be a deployment platform for apps via the adb interface. Though it likely still means that the full graphical interface could be run on it. It's not without issues though and is still very much in development:
I for one, welcome our Google overlords what're you going to make, and will this cause you to check out Android if you haven't already?