Heya Braxus/Scott, I actually got a bunch of old Plus X Pro PXP in 120 that a local shop had in freezer brought in by someone who was unloading a bunch of old gear. It was still in original foil wrappers, no box, and so dating it is a bit sketchy, my guess is roughly between 85 and 92 judging from the paper backing, either way its OLD. I got about 20-25 rolls of it, and after testing it in just about everything, shooting at 64 and processing in Rodinal at 1:25 (I usually do 1:50 but I needed the extra contrast) looks very very good. Actually quite close to your old FXP in 120 in Rodinal, maybe a bit grainy compared to it.
As well, I've found that Tmax100 in Microdol-X 1:0 looks amazingly like Panatomic-X in Microdol-X, at least in 35mm, I'm about to test TMX 100 in 120 to see if it does the same creamy tone thing, that might be a option to pursue as well.