We are in the process of writing several production applications that use XPO from DevExpress. It supports all of your listed requirements with perhaps that it doesn't currently generate classes from an existing database. However, there are plenty of other tools that can do just this. We've had good success with XPO so far. It has been extendable whenever we have a requirement that isn't built in directly. It is an intrusive mapper, though, meaning your must inherit from a base class or implement an interface, but many other mappers are likewise. I would also suggest checking out Versant's mapper as I've heard good things about it, though I've never used it...