OK, this is driving me insane. On my Trek 7300, I have a lot of racket in what I think is the BB area. It happens on each turn of the right pedal when it reaches the most forward position. I pulled the BB and repacked it with fresh grease, BB is in good shape. Now is where the weird part comes in. The noise only happens when I am leaning forward on my handle bars. If I sit straight up, I no longer have the noise.
I checked for loose handle bars, bb, pedals, crank arms, chain, chain hitting the FD and for anything being loose, cracked or damaged and I can find nothing. This noise is driving me nuts.
I'm not sure but if you change the rear wheel I will bet your noise go's away. I think your rear hub needs service. I had the same problem, screwed around with the bottom bracket forever with no result. Try it!