Actually, the passenger A380 only has cargo space of 184 m3 (6,500 cu ft) or 13 pallets, versus 597 m3 (21,096 cu ft) or 26 pallets on the main deck in the MD-11F freighter!
(They haven't started building the A380 freighter yet... THAT will be enormous!)
Screw the passengers. I say fill all the seats with phones :-D