The Death Wobble

[Franchise_24]

Refer to this long drawn out thread if you wish on what has been said thus far:
http://fordbarn.com/forum/showthread.php?t=79078

When I hit a bump just right (normally a man hole cover) the cars front tires shake back and forth violently. At first I had to come to a complete stop for it to stop, after things I've done I can somewhat steer out of it. Here is what has been done (so much it is not in any particular order)'

1) Replaced steering arms (both, balls were egg shaped)
2) Replaced bad tie rod end (other was fine)
3) Replaced guts on both ends of the drag link
4) Replaced guts on both ends of the tie rod
5) Used rubber ball and changed plate on the wish bone
6) All new wheel bearings and races for the front
7) King pins have been pulled - they have fairly new bushings that were reamed.
8) Tightened all perches and any castle nut under there.
9) Set the toe-in
10) Tried good tires from my Coupe on the Leatherback to rule out bad tires

Worried that it might be tracing back to the steering box. Tightened the pitman arm as well so there is no play there.

You can move the tires left and right slightly with the car jacked up and the steering wheel doesn't move

Just wanted to present the list of everything that has been done and see if anyone can offer any more suggestions.

Thank you,
Neal