My rear frame section is bent up from a drop hitch. When I had my rear bumper built, I put the shackle points inline with it. Basically in line with some of the mounting bolts, and a gusset tying the front face and the back face together. It could still get tweaked, but it'd take a pretty...
It'd take some effort/cubic butt loads of dollars to un-fornicated that beauty.
(edit)- I glance through classifieds here, Craigslist, and Hemmings occasionally, even though I'm not looking. The more I look, the more I realize I'm super lucky to have my basketcase, and to have paid what I did.