Shackle relocation options?

[Eagle_SX4]

I was having a strange issue where I was getting death wobble from the rear. Turns out it was just the Chevy drop shackles I was using. Swapped back to the original shackles and everything is good. My theory is that the angle of the longer shackles is to blame.

 

I would like to move the frame side shackle mounting point forward to get a better angle with the longer shackles. Has anyone done this?

 

I know there are shackle relocation brackets available for the XJ. However I have not found any solutions for the Comanche. I am open to welding new brackets on the frame.