I think the reason Mopar didn't offer dual quads on a 440 it's that there was no market for it. They already had their flagship performance motor with the dual quads. Most guys who bought 440's were looking to save money over paying up for a Hemi. Not many would have paid up for the 2x4.
All this hogwash about the dual quad Hemi not being a good street motor will never die. I know from thousands of miles, they are the best street motor. Huge torque AND high rpm power. Very smooth, reliable and easy to drive and maintain in stock form.