Great to see this and to know that some one els is also thinking like we do.

We already using single node clusters in our SQL environment now for more than 3 years.

Especially to make the sql installation server independed.

If the server needs to be replaced we add the new one to the cluster, do the switch over and than remove the old one if everything is running ok.

So it's not only good for scaling out but also for server replacement without a lot of down time and migration issues.