Front End Metallic Clunking

I have a 2001 Grand Prix GTP with approx 140000 miles on it. At about 115000 miles, a noise started in the front end where when I hit a small bump, there would be a slight metallic ping or almost a squeak. The noise started to get worse as time went on. It eventually got to the point that when I would pull in my driveway (there is a slight curbing at the end) it would create a sound that was almost like a grinding metal on metal sound. Here is what I have done so far to try and remediate the problem:

Replaced Struts, Stru Mounts and Springs on all four wheels
Replaced Brake Pads and Rotors on all four wheels
Replaced 2 front wheel bearing assemblies

Even after all this, the noise is still there and is getting consistently worse. The place where I got my struts and springs replaced said that they couldn't find anything out of place or broken in the front end.

The interesting thing is that if I am driving on a rough road and it is making the noise, when I start to brake, the noise subsides almost to the point that it is completely gone.

I read a couple of forums and found something that said to take a rubber mallet and strike each of the tires to see if I could recreate any noise. I tapped the back tires and there was no noise. I tapped the passenger side front and there was very minimal noise. When I tapped on the driver side front there was a pinging sound like something is loose and moving around. I couldn't pinpoint the sound and I couldn't remove the wheel at that time to see if anything was moving. I attempted to move the brake caliper and noticed some small movement but the bolts that hold it on are tight. I checked the other 3 wheels and there is no movement in the caliper. The steering is very tight and responsive and there is no degradation in the braking that I can tell.

Any help anyone can give would be greatly appreciated.

Check the front Bushings on the control arms.

X2, lower controll arm busings, defenatly!