As you know, Ivonna supports testing MVC sites. However, the support is.. it works, but you can't do much about it. However, Steve Sanderson (the author of xVal) recently published a post about the MVC testing framework he's developed. It's based on the same idea as Ivonna: it's running in-process. However, since MVC is much more open for extension, this framework doesn't require "hacking" the runtime. It doesn't require TypeMock and, by the way, is completely free. You can read his post here.

I think it makes no sense to add MVC related features to Ivonna, unless this is really needed, so I'll continue the development in other directions.