Apparently the Vanos unit is the problem. My dealer has drained the oil and replaced it with BMW 5W30 and the noise has either gone away or lessened. I'll be driving it tonight to personally determine the results.
I spoke with Redline and they explained they have no record of any problems with their 10W40 and the 3.2l M motor.
Now I suspect that the Vanos unit is indeed failing, but the problem is masked by some slight difference between the two oils. This is really a no-win situation for me. If the unit fails, Redline will deny responsibility and BMW may likewise claim it is my fault for using non-BMW oil.
I'd love to hear all positive or negative experience with Redline 10W40 synthetic oil and our 3.2l motors.