1994 F-350 -- Death Wobble???

I have a 1994 F-350 Crew cab with 8 inches of lift running 39x15x16 Mickey Thompson tires.  I think I am experiencing what is referred to as Death Wobble.

Every so often between 30-40 mph the truck will begin to shake violently.  It will stop once the speed is 25 mph or slower, or if I turn fairly hard either direction.  It will sometimes occur between 40 and 45 mph (about 1% of the time), and it has never occurred beyond 50 mph.  Also it seems that tempature might play a role: as it has rarely occured at temps below freezing, but can almost be counted on at temps above 60.

The trac bar with replaced with a Bullet-Proof one (http://bulletproofsteering.com/trackbar.html).  The tie rod and drag link were replaced with standard OEM pieces.  The tires have been dynamically balanced.  AND the shake remains.

As I visit the many forums there seems to be no end to the solutions for death wobble, as well as no end to the opinions about it.

I have been messing with this for about 8 months and have not made any head way on improving it.  Can someone please help!!??

ALSO, as an aside:  I live in Casper Wyoming and do not know of any place near by (shop wise) that can be helpful.

i think i may be having this to i have an 84 f250 and im getting a crazy wobble i think it comeing from the front left tire and i cant get rid of it i have 35 12.5 16.5 other then that the truck is all stock but i have the ttb (ifs) front end and its blown could that be the reason and it will shake all the time unless i do a quick turn then go back stright im staying in the lane when i do this but if im doing a long curve it wobbles like the tire wants to come off but a; my ball joints are good any 1 know wtf is goin on?  

hey im pritty sure its the ball joints  

I have had this problem on my 88 f250. It was my caliper locking up while I was driving. I havent had a problem latley but it might be your problems as well.  

I thought so too at one point, but when I had them checked I was told they were fine.