Microsoft Visual Studio 11 Beta has shipped! You can download them from http://www.microsoft.com/visualstudio/11/en-us/downloads#vs
WCF RIA Services v1.0 SP2 (version 4.1.61406.0) is installed out-of-box with Visual Studio 11 Beta (Professional SKU +).
By using this version of WCF RIA Services, the design time scenarios that have been supported for Visual Studio 2010 continue to work on top of Visual Studio 11, including the support for Silverlight Business Application, WCF Silverlight Class Library template, Domain Service class template and Authentication Domain Service template. The project templates will be targeting Silverlight 5 by default.