Just wanted to share, I managed to sideload the current Spotify .apk, and was greeted with a sideways Spotify login view on launch. Luckily, using Sony's Quick Remote App once paired, can use a touchscreen mode with a mouse cursor to access the app. This is one step up from Google's Android TV remote which has a touchpad but no mouse cursor support.
Once I got past the sideways login, Spotify loaded properly (not sideways) and was quite usable using the Sony app in Cursor mode.
So give that a shot for those looking to get Spotify on the TV. Alternately, I am curious for anyone with the physical Sony Smart remote if THAT can somehow be used as a mouse cursor.
There's a modified version floating around that has a launcher icon, too.
It's still the same phone app, but you can play to the device without it being in the foreground - which won't work with your normal one you side loaded.
I just Emma sometimes. But if I know I'm going to be all over the house I load Spotify proper so I can change songs and whatnot from my phone.
See this comment for the apk
http://www.reddit.com/r/androidtv/comments/3v03t1/apk2tv__takes_android_apps_and_makes_them_android_tv_compatible_to_some_degree/cxj565c