Possibly, but that's not what Spotify's for is it? The whole point of Spotify is so you DON'T need a massive personal library. :)
Plex server running with a massive personal music library and remote access set up?
I love Plex but I haven't used any of the paid features since I've had the pass. (lol)
Google play music is a good option, you can add 50,000 tracks from your own library for free, then stream them / sync them across various devices (android / ios / Windows, etc)
Thanks for this always wanted to try this out