Bionet, thanks -- I replaced the sway bar end links a few weeks ago and double-checked a couple nights ago to make sure they were tight. They were, so all is good there.
OK, solution found guys, but it's embarrassing to have to tell my story. Hopefully this will help you avoid my mistake. Here goes: I replaced the sway bar bushings the other night, as I said I would. The driver's side was a bit more worn out than the passenger side. But that repair didn't fix the problem.
Sooo, I broke down and went to the local independent shop with a good reputation, but which I've never used before. The owner lifted my car up and thoroughly inspected all suspension components. I went on and on about what I had replaced over the past few months, including the control arm bushings. He grabs a crowbar and pushes up and down where the bracket meets the frame on the driver's side. YIKES! Movement. Not good. When installing the control arm bushings, I ended up stripping the bolt holes. I must not have had everything lined up properly, even though I don't remember any unusual resistance as I ratcheted the bolts in. So, he tapped new threads, installed new bolts and away I went. I've got that great BMW ride back once again!
Moral of the story: Make sure you get the control arm bushing bracket holes lined up with the frame holes perfectly before installing the bolts. Thanks for everyone for their input!