Question:
There are many aspects to your product that are appealing; however, it appears as though there is a fixed architecture based on a centralized database.
Is it possible to have a distributed database architecture where individual clients have their own specific data and communicate with a central database for updates?
SQL Server is ideally suited for this, with distributed, royalty-free SQL Express clients communicating via a service broker to a centralized main SQL Server. However, from my quick assessment this capability does not appear to be supported within your framework.