You could get these: http://cgi.ebay.com/U-Weld-clevis-mo...d=p3286.c0.m14
and modify them to fit, by welding them to some 1/4 or 3/8" plate steel, drilling holes in the appropriate places & bolting them to the stock hook location(s). Then hang clevis loops of your choice...
I would cut as much length as possible off them before welding to the brackets, maybe even angle them back a little to keep as much approach angle as possible.