As Abigail mentioned, this isn't really a new technique, but it is one that you are drawn to as your system becomes more complex. We had this architecture at eCircles back in 1998, and we're using it now at another site where I'm active, and for exactly the same reasons that you mention. I'll add that decoupling the front-end from the database in this way makes applying changes, and tuning the database (and the queries) a lot easier.

Michael