I have just put together another SONOS plugin, this time for Shuffler.FM!
It is still a work in progress though… I have the public genre streams all available and the associated tracks but no specific user content. Shuffler does not support username/password auth for their oauth api so it make is a little more difficult to get access to that content. Also the only content sources that are currently supported are official.fm and Soundcloud. I am working with Shuffler to get their streams available and I will never be able to support youtube streams.
Well if you are still interested simply use the following info in the correct places while following the instructions from http://inburst.io/soundcloud-on-your-sonos/
Endpoint and Secure Endpoint URL: http://inburst.io/sonos/shuffler/SonosAPI.php
Authentication SOAP header policy: Anonymous
Container Type: Music Service