What was the end result after your alignment? Any more issues?
I just picked up an 05 F350 4x4 with 93k that is stock. I experienced the death wobble exactly as you described: going into a turn, slight bump in the road, steering wheel shaking violently then the truck shaking, couldn't get it to stop until exiting the turn. This was a freeway interchange ramp, approx 55mph.
I have no lift. I have new tires on the way and know I need an alignment. This was the worst shake I've felt on any vehicle I've ever owned. Hope I can get it cleared up.