Timing or Cams? What's the knock?

[furiousg]

I have an 05 with 20,000 miles. Lately I've been getting the annoying knocking sound under the hood and it is getting louder. It appears to be coming from the passenger side right off the valve cover under the timing belt shield. At first I thought it was the cam gears hitting the shield so I took it in to the dealer. The guy said that he didn't notice any noise so I asked him to come out and look at it. I started it up and like normal, no noise right away. I asked him to just wait and listen. Eventually you begin to hear a slight knocking and as the car comes up to tempature the knocking gets louder. He told me it doesn't make any more noise than any of the others he has heard. Frustrated I left. I went home and ripped the shield off and let my car idle. The noise was still there but not as loud. WTF? Couple of weeks later after searching the forums, I found the TSB for the Cam bearings. I took the car back to the dealer with the TSB and asked them to check it again. After a little while, the guy comes out saying he didn't hear the noise. I can hear it. Anyway, after two dealer visits and no results, I don't know what to do. Anyone know any good dealers in the Northern VA area that can fix this or does anyone know what exactly this noise is so I can just take it in and be like, here's what the problem is.