So the bushings you're looking for are in the upper part of the shackle, correct? I'm assuming the upper pin is tight to the steel of the frame mount and doesn't rotate in it. Does it have a lock bolt like the lower pin does?
With the dimensions you gave, you could buy one of the spring eye bushings and have it machined to the correct OD to fit in the upper part of the shackle. I'm sure you have a friend with a lathe, right?
