would it not be possible to adapt a 28mm PC Nkkor to the Hasselblad /Fuji
That was I have done before buying the 30mm Xpan.
Nikkor 28mm PC is big and vignetting at corners limited it's use.
Tried also Super-Angulon-R PC 2.8/28mm, even bigger and vignetting too.
Framing with the 28mm, I used 15mm Finder with a sort of adapted with black tape strips.
This is not precise framing.
Xpan 30mm is very special lens and not easy to use and find subjects to match it's field.
With the 30mm viewfinder, I use the "level" which is usable only for horizontal.
When in use Xpan 30mm excluded for many months my other 45mm/90mm.
Must be used with speedy film, with the filter it's an equivalent f/9 wide open: to be closed a bit for best IQ, so f/11 or 16 is the norm.
Results are great.
Comment on the price...
I don't understand the high price asked for this lens, maybe because it's good (people tend to keep it), and rarity .
As side note, old Noctilux lenses are even worse in high price, mainly 1.2/50 asph. variety, less with 1.0 which remain very expensive.
Sometime, the price asked for 1.0/50 is higher than the last 0.95/50 asph.