I would venture to suggest ASP.NET MVC Music Store (http://mvcmusicstore.codeplex.com/
) don't look at the word Music, you can sell anything.
This, of course, not CMS. But in this store a lot of examples and documentation. The code itself is simple and straightforward (less than 1000 lines of code).
The advantage of this approach is that instead of a hulking monster on php, You will receive the strictly necessary functionality, but at the same time and understanding how it works.
There is still a good book Steven Sanderson, ASP .NET MVC Framework with examples in C# (for professionals) — 2010
just on this topic.