Well Marco's probably been the first one to blog about it. My only comments are:
a) Change the name. PRISM is already a pretty well-known project in the Microsoft camp, also known as Composite Application Library for WPF/Silverlight
b) Two years ago I said at a session at TechEd that going down the VCL.NET route is a mistake because of the lack of roadmap and support from third-parties. I received a lot of feedback (i.e. read hate mail). Ironic...