...boy, you guys are alot faster than me! I've always made my bookcases with a fixed center shelf...at least the longer ones. The time it takes to dado and install the shelf, true, isn't that much, but then you have to factor-in the extra piece in the faceframe and all that goes with it...as an aside, I usually finish the case before installing the back; it makes for better/easier spraying...shelves always get at least an 1 1/2" hardwood strongback/face.
cg