Indeed, we just released both R80.20SP and Maestro. Public download for everyone is not available right now and it will be available in the future.
The reason is simple:
Since concept of Scalable Platforms (especially Maestro) may be new and challenging for our partners and customers, we would like to closely escort our first installations and go together throw upcoming issues (if any).
We believe, this kind of service is win-win for both sides, since customers and partners will get closer support, and we will learn from their questions and challenges on the way.