SMOC,
The A380 passenger aircraft will never be converted to an A380F, just like a 747-400 will never be converted to a 747-400F.
The A380P2F, like the 747-400BCF are converted passenger freighters. That sort of aircraft is not a true general freighter, it is however a volumetrically efficient package freighter.
Fedex has expressed interest in the A380P2F.