Squealing noise!

I have a 96 Mustang GT. My problem I am having is a whining/squealing sound coming from the front of my car. I have been having the problem for a month now. Its not the engine because it only happens when I am moving. Its not the transmission because it happens when I am out of gear. I changed out the break pads and rotors thinking that was the cause of the problem but it didnt help. I also thought the dust shield was rubbing against the rotor but its not. The wierd thing is that the noise doesn't change frequency or speed as I speed up or slow down. Its really irritating and any suggestions on where to go next would be greatly appreciated. Thank you in advance!
 
If it's only occurring when the vehicle is in motion, look for a chassis reason (e.g. wheel bearing).

It's hard to believe the noise only occurs when the car is moving but doesn't change in intensity or frequency with speed. Can you better describe this noise or post a vid?
 
It can't be the throwout bearing because I just had the transmission rebuilt less than 2000 miles ago. I dont know how to describe it better. Its just a squealing noise. Its a metallic squealing noise. It sounds like something rubbing on the rotor but nothing is. I'm totally stumped.
 
Are you certain it doesn't do it when idling? I'd check the belt tensioner. SN95's had an aluminum tensioner that would fatigue and slightly bend over time causing a belt squeak. Have you recently replaced the serpentine belt?