I believe you are right. I checked the entire front end and found nothing. I checked the tranny and it seems fine; fluid is perfect.
I drove the car again last night and the shake was horrible, but no grinding or 'failed parts' noise. I have always tested drive-shaft problems by trying the car in different gears to see if the shake is always at the same road-speed or RPM. The shake on this car starts before getting to 10mph, so regardless of gear I try, the tranny is always still in first before the shake starts.... it also shakes in reverse, but not as bad.
Tomorrow is the start of my weekend, and I am going to climb under and start exploratory surgery. My money is on the center support bearing! At least I hope so, because I have one in the garage. It has been making noise for the past few months, but I have been too lazy to replace it. I guess I am 'paying' for not keeping up with the maintenance like I should
I'll let you know what I find.