I have some possible candidates found to re-drill to the sbp if a person was to change the backing plates but the unknown measurements are have stopped me dead in my tracks. Depending on the offset differences what I am looking at might not work.
Right now it is said that you can modify the front drums to use on the rear. That may work for now but my local stores have already dried up for the front drums so I am thinking they are going to be gone before long too.