I am working on rendering a dynamic form in an ASP.NET MVC view that will meet these requirements:
How dynamic are your field definitions? If they dont change very often you could use code dom to generate the model and controller once the definition is created. I have not tried this in ASP.NET MVC but it might be a good way.
http://msdn.microsoft.com/en-us/library/y2k85ax6.aspx
This article uses code dom for ActionLink generation.
http://blogs.msdn.com/davidebb/archive/2009/06/01/a-buildprovider-to-simplify-your-asp-net-mvc-action-links.aspx#comments