they look awesome. For those of us wanting to do it ourselves, what book are you talking about? and what is muslin?
Here is one of the books. http://www.amazon.com/dp/1931128006/?tag=stangnet-20
The other was called Custom Automotive Interiors by the same author, but it may be too old to list.
Muslin is a type of material. My aunt said it was like a cheese cloth. Very thin and used to keep your thread from pulling back through the foam. Basically when you pull your old covers off you will see what I am talking about. It will only be on those pieces that have the foam on them.