Thanks for the all the feedback. I really appreciate this forum and all the sound advice and experience that is shared.
I didn't realize that as a new member that my post would take 1.5 days to actually be approved to be posted to the forum. So a lot has transpired since I originally wrote the post/question. First, I added the question on another forum that posted it immediately. I began getting feedback and as a result I began testing some ideas.
I removed the fan belt and rotated the fan. I was very happy to find that rotating the fan counter-clockwise created a grinding clunky noise that sounded as if it could be the source. However, rotating clockwise... no noise. I wasn't completely convinced so I dug a little deeper. I removed the a/c belt and then the fan. I fired up the engine, no noise! I shut it down ASAP.
Porsche 88 911 Start Up No Belts on Vimeo
Next, I rotated the alternator shaft back and forth, the noise appears.
Porsche 88 911 Alternator Grinding on Vimeo
I'm convinced that this is the source of my issues. Unfortunately, I just couldn't believe it was going to be the alternator because a new reconditioned Bosch was installed in late August. In hindsight, it should have been my first suspicion, but it wasn't. I went to total engine failure in my mind. Ive never been so happy to be wrong!
I got the car home and removed the alternator. I'm going to take it to the parts department tomorrow and exchange it for a new one. My Bosch warranty should cover the cost. I'll replace it and hope for the best. I may even take the opportunity to have the fan and fan housing powder coated while it's disassembled.
Again, thanks to everyone!