OK, let me put a different spin on it.
My XJ makes a growl as well....only when turning left, only on acceleration. Steering wheel is 25-45% turned to the left at the time of noise....usually happens when I'm trying to pull out of a parking lot. Mine is definately front end noise...just have no idea where. No hard/flat spots in the steering, either. No vibes that I can recall. Very infrequent, but happens often enough to scare me.
89 XJ, fully stock
*edit*
Forgot....I also have a squeak from left front.....very very faint while going straight, loud and annoying when turning in either direction. I do believe that's a wheel bearing, though.....don't know if it's related at all