So the researcher mentioned above has confirmed the Ss does predate the varroa mite in vitro. They could not get good results from their hives however.
They are currently in the process of writing a manuscript of their results, so shouldn't be long. Will put a link up when I get.
Additionally, research is being conducted by a couple guys at a University in Holland, and more is about to begin from Laval University in Quebec.
Looking promising... but quite a variation in results. Have any of you tried Ss in your hives?? What did you find?