I love that you went up an encapsulation level compared to what even the OP was asking. The ability to scale and customize on a single customer level is amazing. Do you find yourself capitalizing on this capability fairly often?
80% of my clients run the same "master" version while 20% have minor customization's specific to their organization.
I don't want to end up maintaining 20 different applications, but being able to do minor modifications to the UI or data model on a per customer basis has been a nice selling point.
