Thanks for the responses. While WebFormsMVP is what DNN is using, I want to concentrate on MVC as a full skill I want to acquire for work as a .NET developer outside of DNN, and if I can use it inside DNN as well, the better.  It seems it can be used but only for when using default controller and index.

I know DNN is not migrating to MVC. There are hybrid ASP.NET applications which use both WebForms and MVC and wondered if DNN can be used like them.

A couple of points about DNN and MVC.

1. Yes it is true that there are hybrid webforms/mvc apps - but in these scenarious Page1.aspx is using webforms and Page2.aspc is using MVC - ie the pages are independent.  DNN uses a single physical page Default.aspx, so any MVC module has to live inside a webform. 
2. Webforms rely on a single <form> tag in the html to handle the event model.  MVC pages can have multiple forms.  HTML does not support a <form> within a <form>.  Therefore any MVC module will not be able to use its own <form> and will have to rely on the base <form> in the Default.aspx.
3. The lack of a form means that some of the MVC helper methods will not be able to be used.
4. Normal MVC routing deals with the full url, but DNN's FriendlyUrl provider manages its url, therefore to support MVC modules we will have to manage the routing.  This will mean that MVC module developers will not be able to use some of the MVC routing helpers.

Given the caveats above I believe that this is acheivable - as long as MVC module developers realise the restrictions in (2) and (3).

After Easter I propose to start working the routing piece for the dnn labs project.

There's a hanselminutes podcast where one of the two coders of WebFormsAMVP is interviewed. While webFormsMVP is a good solution, I want to learn MVC as a new way for creating web apps and because that's the direction many developers/companies are going to. Not really want to use a niche framework for testability usage.