It seems to me that there is no name yet for this kind of framework you are all talking about in this thread. I call them for the moment just RAILS-like Frameworks: Frameworks that increment productivity by orchestrating other existing frameworks with the purpose of solving the basic needs of most web applications, but at the same time hiding all the complexities from the developer.
Thanks to the Convention-over-Configuration principle, these frameworks avoid the need of defining lots of configuration files usually required by the frameworks they orchestrate (like Spring, Spring MVC, Hibernate, Log4J, etc.), assuming configurations by default based on naming, structure and metadata included in the same classes definitions.
Thanks to the dynamic languages that these frameworks make use (like Ruby, Groovy, Python, Clojure, etc.), with the exception of SpringRoo that implements dynamic behaviour in Java by using AspectJ, the functionality that belongs to the frameworks underneath are extended and are made available to the developer in such a uniform and elegant manner that he/she is just aware of the underlying technologies.
Finally thanks to the Scaffold technique, unit tests, integration tests, controllers and views are automatically generated for the main functions (CRUD) over each one of the domain objects defined by the developer.
In the .NET world nothing has been developed yet, following all the previous definitions. But nothing prevents that from occurring soon. There are great frameworks, tools and libraries already available in the .NET world that can be orchestrated by a new RAILS-like framework made for the CLR. There are Unity, Spring.NET and Castle Windsor among others for the Dependency Inyection needs. Entity Framework 4, NHibernate and iBatis.NET are pretty good .NET Persistence Providers. ASP.NET MVC have strongly arrived with support for various Template Engines besides the traditional ASP.NET.
Even if nobody achieves to use a DLR language to build this kind of framework, anyone with enough will can follow the SpringSource path and implement a RAILS-like framework with some static language like F#, C# or VB.NET, making use of an Aspect-Oriented Container (like AspectSharp or Gripper-LOOM.NET) to obtain dynamic behaviour.
I would love to know about any group of people trying to develop such framework in .NET.