If you saw Nigel Ellis' "Introduction to SQL Server Data Services" presentation at MIX08, you will remember the Litware HR application that Nigel demonstrated.  This application is built using the SSDS service by Eugenio Pace and members of his team.  Eugenio discusses the architecture in his blog here and how he built this multi-tenant application here.  He talks about the pros and cons of using SSDS.  Good read.  He promises to go deeper into how his team built the application and the challenges they faced.  Look forward to hearing from you Eugenio.  This feedback is very important to us as we build out SSDS.  Thanks for the help.