Well, this is something I've wanted to do, even before I bought my first bike.
I just picked up a 1974 CB750 project that the PO had already halfway completed- this thing came with TONS of spare parts (see photos below). Not pictured in the photos below, there's a brand new squarish cafe tail/seat that uses the stock hinges, a NOS CB360 tank, NOS 1969 side covers, velocity stacks, the original tank, and a bunch of small parts/cables/hardware that would have been hard to photograph. If you follow the link to the Flickr page, I've added notes over all of the parts (some of which I'm not sure about- any help here would be greatly appreciated).
flickr.com/gp/felixpomerantz/h84F5W