Are there any actual studies backing up the efficacy or benefit of these probiotics?
Yes, though it's still early. There was a study conducted at the University of Washington in Seattle concluded that IBS sufferers could experience both short-term and long-term relief with the use of these specific SBO's.
And then a study conducted at one of the most prestigious institutions in Ecuador , concluded that consuming of SBO's could help significantly reduce the time spent with symptoms like diarrhea.
Overall, when it comes to studies, we must remember that drugs are much more lucrative than nutritional supplements, and therefore easier for big companies to fund expensive studies.
Similarly, much of the research done on probiotics has been done by companies with a vested interest in the outcome (i.e. yogurt manufacturers) and therefore biased. However, as the benefits of SBO's become more widely known, more and more research will emerge.