I have been working on this for better part of a year during my free time at work. I finally have a working example of how to do fully on DLL plugins for ASP.NET MVC. It is the gathering of many partial solutions and blog posts to make a functional example.
This code can be way better. This is meant as a starting point for anyone that wants to do this. The Virtual Path and File providers are one place that need to be updated.
Note: This is a VS2012 project in MVC4 however this code will work in VS2012 and MVC3.