Stanley
Sorry to advise you that you were a bit wrong re. loading of the 767. I've seen a manual published by Boeing, and the 767-300PF can indeed hold ULDs in twin-row, 24 125/88 in total on the upperdeck. The -200PF can hold 21. If DHL are buying anything, it will be the SF, a converted pax aircraft. I have not seen any manuals on that version.
This makes the -300PF fit in between a DC-8 (18 positions) and a MD-11 (26 positions).
Might be some truth to the rumours, but still nothing official.