Due To not having any gauge (7psi switch IIRC) movement, I would suspect something awry with your LPOP. LPOP sucks the oil out of the Pan and feeds it to the engine oil passages (main bearings, rod bearings, HPOP resevoir, Oil filter canister, etc) If your not getting any oil to your canister, or gauge movement, I would check the LPOP.
LPOP is located behind crankshaft pulley/dampner, and is of a geroter type design. They are not failure prone, but they do sometimes have issues. Another item to check would be the oil pressure regulator being stuck in the open position.
-copy/paste of Ford TSB-
Low Lube Oil Pressure:
Some 6.0 engines may exhibit low lube oil pressure caused by leakage in the high pressure oil system. To determine if this is the case, remove the oil filter and hold down the oil drain valve on the left side of the filter housing with a screwdriver. Watch for oil flow with the engine cranking. If flow is present, diagnose the HP oil system for leaks. If no flow is present, diagnose the lube oil system. Broadcast Message 1044