I replaced my front driverside hub assembly yesterday as I was getting a squeak and a slight harmonic from the frontend corresponding to wheelspeed and unaffected by brake application. The hub was plenty loose and was definitely in need of replacement...a quick testdrive proved that the squeaking was gone.
Fast forward to my way home from work sans top...coasting up to stoplight and wouldn't you know it the harmonic groan is still there. Check it when I get home and, yup, tons of play in the pinion.
VERDICT: It appears that the original gear setup on BOTH axles wasn't done correctly and that it wasn't a bent driveshaft that caused my rear to go. So for those looking to have gears setup make sure that the person doing it is experienced and make sure that some of the setups they've done in the past aren't having issues. Luckily I caught this early enough that it looks like I just need an install kit and have the existing gears re-setup.
--Ian