Drat. It's not the magnet. I removed it from the spoke, coasted down the driveway, and phantom noise is as loud as ever. Noticed it's only noisy when I have weight on wheels. I walked it back up the driveway and was nice and quiet.
Not sure on bearing adjustment StephenH. I was kind of thinking bearing noise, but it was still making noise while I turned a few figure 8's in the cul de sac.
I think it may be the spokes as Bill suggested. A few are sprongier than the rest (that's a technical term), and some make a creaking sound when I squeeze them out of rest.
Even if it's not the source of the noise, it looks like I need to adjust some spoke tension. No spoke key here, will prolly just take to the LBS Wednesday and not risk borking a new rim.