I am in the middle of a bookcase door also. I have about 3/4 of a custom ash library finished and I am still toying with various designs for the door. it can be done with either a pivot or a set of hinges. For me the real challenge seems to be keeping the frame from racking over time due to the weight of the books, as I would like to avoid a roller on the end. I also plan to use a set of counter weights to open the door that are reset when the door is latched, and of course a pivoting book must be the opening mechanism. Has anyone done anything similar? Any suggestions of the pivot versus the hinge? I found a couple web sites that may be useful for others:
http://hiddendoors.com/products.htm