Viewmodel extractors in ASP.NET MVC

Last week, I wrote something on assembling viewmodels in ASP.NET MVC. In that post, I said it would be nice to have a layer between my controller and my domain services that would assemble viewmodels for me. This would work one-way. In the other direction - from controller to domain services - I would just take a piece of my composite viewmodel and pass that directly to my domain services. Well, that last part didn't really work out eventually. I found it hard to find real-world scenarios where I cou...