I got a lead on a replacement bumper for the Panama. It was 3.5 hours away, but one does not turn down a bumper for $100.
Made the drive and met a nice family. The guy has a '54 Panama also. This was had a Continental kit added to it, non-original paint, but fully original interior in good shape. A solid driver.
The bumper is in much better shape than my original, though definitely not perfect. My old bumper had all the chrome peeled off the lower half, and the lower edge was all sorts of bent from jacks in the past.
The new one had some bad pitting on one of the guards. I replaced it with a good one from my old bumper. I polished out the other defects the best I could. I cleaned all the rust off the inside, converted the remainder with Ospho, then painted it black. The overall finish is much better than my old one but still not perfect. For $100 I'll take it though.