I'm just reading this now and I have the same symptoms. When I pull out of a parking spot I get a squeak that matches speed and then it stops. I've had this for months now and it drives me crazy.... Mine sounds like its coming from my front axle though?

 

Would take a close look at the U-Joints, (tight dry u-joint).

 

No ujoints, RCVs

 

When I had the bent flange the noise was not always there and was much more noticeable when I was making a turn. Check it out.