The valve covers have a separate perimeter seal versus the spark plug holes so they wouldn't necessarily be leaking. It's kind of an ugly area to see into, but you might try dabbing a rag down next to the engine mount on each side and see if one comes up with oil on it to try to isolate the leak a bit further.
As far as the timing cover leaking, it's possibly, but considering where gravity would be naturally taking the leak in that area, I'd say it's less likely.
Rick
