No, and you'll never see it back. the reason being SIS has a large IOPS footprint and that doesn't match with what Microsoft has planned for Exchange. Since they removed SIS they have lowered the database IOPS requirements so low that you can pop a database on a SATA drive and be perfectly happy. And since you can get a 3TB drive SATA drive for $150, it seems a worthy trade since SIS only saved typically 25%-35%. This also coincidentally makes it easier (and cheaper) for Microsoft to supply storage for those 50GB mailboxes on Exchange Online.Has Exchange 2013 returned Single Instance Store? I really miss that feature.