I have been working on a project at home for which I am using DotNetMock to create mock objects for my unit testing. Unfortunately, DotNetMock has a couple of problems with its dynamic generation features. The first is that it does not currently support methods on inherited interfaces, and the second is that it does not work correctly with non-primitive value types.
DotNetMock seems to be the extension of NMock. Many of the interfaces are the same, and NMock hasn’t been updated since last May. However, there seems to be only one guy on the DotNetMock project, so I’m not sure how long-term the project is.