a hack saw can't be more than $10! Chop of the end of the bolt, then file (or sand) the edges. Easy, and much better than terry cloth!
I ended up doing a pretty decent job repairing this. I had some 1/8" x 1" bar stock laying around so I fab'd (using a hack saw, file, hammer and power drill) a 4 or 5" long strip with a hexagonal hole to fit the nut. I just drilled the hole about the right size, then used "excessive force" to smash the nut through the bar stock.
Next I fiddled the metal behind the cross member from the opening in the back, then used self tapping screws to hold it in place. I was pretty impressed with the results. Would have done a much better job if I had access to a welder of some sort...