I've been through this and found the noise coming from the little round metal fixture in the ash tray. I assume it is for extinguishing cigarettes. After months of trying to find it I put my finger on the fixture and the noise ceased immediately. I think a little silicone around the perimeter will shut it up for good. Taking care in application will leave the fix pretty much invisible.

 

I don't have the ashtray installed, in its place is the control head for the 9500ci which is mounted on a velcro block. I did ck, its not the cause. This literallly sounds like its below the center console cutout for the ebrake.

 

Any wire couplings under there that may be jiggling around. That's what I'd bet on it being.