I understand your concern over the code. Some people understand TheBeerHouse for what it is, as a great learning tool for getting them started with ASP.NET MVC, others are trying to make a business of setting up websites around it. I can understand the point of not wanting to use outside projects that may not be supported if you are setting up a business, but that wasn't the goal of TheBeerHouse.
The point of ManagedFusion.Web.dll and ManagedFusion.dll was not to add functionality that will stay with TheBeerHouse in the future, it was to fix some of the gaps that were missing in the MVC framework. Over the course of writing the book during the last year, we removed 75% of the ManagedFusion libraries code that was originally in TheBeerHouse code base, because the same or similar functionality was added by the MVC framework over the course of the preview releases.
That is why they weren't mentioned in the book, because at the time of writing we didn't know what was going to be there and what wasn't by the end of the book. Also we do talk about the attributes from the ManagedFusion libraries in the book, we just don't mention were they came from assembly wise, for example you will see HttpPostOnly
mentioned quite a few times in the text.
Secondly, I am sorry you are not getting warm and fuzzy feelings, but StackOverflow and SourceForge (do people still use this) isn't really an exhaustive search. If you checked code.google.com and codeplex you would have found many more references, including the actual source code:
Which is very liberally licensed, using the BSD License. So if you are inclined you can copy and paste just the code from ManagedFusion.Web.dll in to TheBeerHouse and pretend it was always there.
Other than that I don't know what to tell you, TheBeerHouse forums and even the P2P forum has covered this topic ad nauseam.
I wish you the best in your rewrite, you will find 4 action filter attributes that come from the ManagedFusion libraries:
I hope this adequately explains the point of ManagedFusion, and that it is my hopes that it will eventually be removed once the MVC framework catches up to some necessary features that I felt the MVC framework was lacking.