All without changes to your C# code at all. Awsome.
Just watched Scott Hanselman's ADO.NET Data Services talk from NDC09. Rather good, so go watch.
Given that it (ADO.NET Data Services) is agnostic of EntityFramework, Ling2Sql, NHibernate, or MyHomeGrownOrm, seems like a good basis for implementing simple CRUD style services.
Looking at it I can see the appeal and its a good way to go. You could easily plug in a mock objects with test data pretending to be your database for NUnit testing your code with ease.