Pic is taken from front of car. In the lower right corner you can see transmission drain plug. I'm curious what's behind the black panel, as I can see some signs of leakage behind it (the darkened area below the panel)

 

The ring gear on the flywheel/torque converter.
If your car is a manual Honda calls it "the clutch cover" page 13-7, 2007-8 service manual. If yours is an automatic it is called "the torque converter cover" page 14-233 of the service manual. It looks to me like an automatic.
If the source of the stain comes from the engine side of the ring gear the crank shaft seal could be leaking. If it is from the transmission side look to the transmission for a leak. Are you having to add either engine oil or tranny oil ?

 

should have mentioned it's an automatic. i have not had to add fluids for at least 9K miles (that is when i last changed oil and a/t fluid). the dark spot is not wet, there have been no drips on my driveway. if its what you suggest, it sounds like pulling the engine would be necessary to repair.

 

This is seepage or rather sweat from the rear crank shaft seal; if there is no liquid oil, just "oily dust" it is considered NORMAL!
I have this on my 07 as well.

 

yeah, i'd say "nothing to see here"----I took the panel off, felt around for some oil, and just got the "dust"