Can you smell gas? The fuel damper is in that area and they have a propensity to leak, but not with out the gas odor.
Can you "confirm" it is engine oile and not tranny fluid? High pressure lines and cooler are also in the ares but would need to "squirting" the oil up there.
Same with the power steering lines.
Take it to the spray wash and get off all the old oil then get a mirror down there and start looking for the source.
It's hard to tell you with out seeing first hand.
Does the #5 spark plug look any diferent than the others? does the engine run or idle rough?
Have you done a compression check? all cylinders should be near the same compression.
Good luck, and post back this is curious.