Chevrolet Repair: Cant stop what appears to be a belt squeal, camshaft lobes, tensioner pulley

Question
I have a squealing noise associated with the serpentine belt on my 2003 Silverado 1500 w/4.8 V8. I have replaced the tensioner pulley, the whole tensioner assy, the idler pulley, the serpentine belt (napa/gates), I have replaced the A/C belt and tried the engine without the A/C belt in place. The noise will get less after running the engine but the noise is still there. When I am on the highway I can hear it and it sounds to be the same frequency (tone) as when I am idling. Could the fan assy cause this noise? I don't know much about that clutch assy on the fan, how does that work? Should I replace it? Does it wear out? I have 100300 miles on this truck.

Thank you for any help.

Answer
Really bad news. We had one in the shop here and it sure does sound like a bad belt.  However it is not a belt noise take all the belts off and you will find that it still does it.  If it does (which I hope it doesn't) you will find that you have a lifter type noise which is due to worn camshaft lobes.  You will need to replace the camshaft and affected lifters to fix the concern.