Eventually Microsoft decided to focus on LINQ to Entities for the next .NET 4.0.
See the ADO.NET blog and this entry.
This is a great decision, because their Data Access offer was much more than confusing to users, with too many ways to access the same data and too much overlaps between their different technologies.
The good news is that Microsoft recognizes the importance of having an intermediate Business Model to integrate data. This is a great milestone for the whole software industry!