I had NCrunch installed for the VS11 Dev Preview, and I find that it still works in the Beta.
However, when I converter all the projects in my solution to .NET 4.5, and reloaded it, "Enable NCrunch" is disabled in the NCrunch menu.
I think the issue runs deeper though, because the Resharper test runner wouldn't run my tests either.
All this is with VS11 Beta on Windows 7, by the way.