Did you find out what it was? Today I noticed the same light whining noise that appear to be coming from the front drivers side. Tone does not change with clutch in or out. I clearly heard it coasting downhill in neutral between 65 and 50 mph. I don't beleive it's TC almost positive it's a wheel bearing going out...
What I'm going to do is jack the car with all wheels off the ground, have a helper to run in at 60mph in gear, take a stethoscope and find a source of the noise.