Hey everyone, recently been playing around and was able to get a nearly fully working google tv experience on my Sony X900H. This will apply to shield as well.
Follow the instructions from this site: How To Geek
Install the two apks (both are needed), enabled adb, uninstall default launcher.
From this point depending if you have access to the new Google tv app or not (I don't in Canada) to pick your streaming services and work your watchlist go to a new Google search and type "What to watch". You'll see a settings icon to the top right of the results. Click it and hit edit services.
This will make the "For You" tab work for you. You can rate shows to help it along.
For the most part everything works. You won't have the new settings menu and clicking the screensaver button in the menu will crash it. (Reloads)