So, thanks for the help! I've narrowed down some clarification.
I did NOT replace the sway bushings, and actually one is held in by one bolt as the other rusted and sheared. I could drop the whole bar and test drive, that would narrow that down.
It's not fender rub, know what that sounds like. Way heavier and more metallic than that.
Bumping hard on one wheel does cause the problem, not as frequently, but the sound still seems vaguely centered. Which is odd.
When taking off the wheels, nothing seems wobbly, is there a specific lateral runout I should be looking for in wheel bearings?
Further thoughts?