Kevin,
I don't know your exact situation do I'm not sure if this will help, but I will say that I do some similar stuff with the aid of MvcTurbine and the existing conventions around mvc views. Here is what I have:
A basic site layout including a master page, css, scripts, etc.
A defined way to render a list of items, like a grid.
A defined easy to render a form, with date pickers, html editors, etc.
A need to extend this app to make project-specific administration.
I use turbine's embedded views to store the master page and default editor and display templates.
I use turbine's meta data attributes to allow control over how editor fields are rendered (like, say, whether to show a string property as a text box or a html editor.
I use turbine's global filter registry to set the master page to my embedded master page.
I put all of my stuff into the Shared directory, which allows it to be overridden on a per-controller basis (shared is used last, and mvc does not see the difference between Shared folder in the project and Shared in the embedded view assembly)
They way that I do it still requires that other coders build their own views for each of their actions, but those views only contain a call to Html.DisplayForModel() or Html.EditorForModel().
If this sounds like it could be helpful, I can give more details.
Darren