I just bought a book from Amazon.com called Cooking with Coconut Flour. In the book the author states that because coconut flour reacts differently than normal flour, she would only recommend you use 25% coconut flour in each "regular recipe".
I made choc. chip cookies with a friend yesterday who is gluten intolerant. I wanted to use my coconut flour (for the first time), so we experimented. I used the regular Nestle's choc. chip recipe which calls for 2 1/4c flour. I usually only use 2c of flour because I like my cookies thin. So we used 1/2c coconut flour, and 1 1/2c rice flour. We definetly needed more liquid so I threw in an extra egg. To our delight the cookies came out perfect! You couldn't taste the coconut and they tasted just like cookies made with regular flour.
The book I bought has recipes using only coconut flour exclusively. I have not made any of the recipies from the book yet.