I've had to go the route of SQLite for a couple of my projects where I needed the simplicity of SQL and no layer of authentication or such that EDB has. While having Single file is awesome, it's not a deal breaker.
Has there been any further progress on the EDB Single file? Or should I maybe look at DBISAM, which wouldn't be single file, but would not have the layer EDB has to just simply open the DB and go?