I found the mystery bushings in the shed o' many things. Cross-referenced the number and it's part of an Energy Suspension kit for a 70's Camaro. Don't think this would work, but the ES catalog had some custom parts you might try.
I was not proposing a solid mount. With the bushing kit, I wonder if you could make a stack - plate, bushings, plate, bushings, washers - bolt and sleeves to locate. Some head scratching involved. Or you could cut off the mount flange and weld it on lower down the face of the crossmember.
Sorry I don't have a magic solution.