Ive sucessfully modded a couple of Panasonic JU257 drives a few years ago as used in the first lot of escom Amiga a1200s.
These drives simply requires the switching of pins 2 and 34 to work in my non escom amigas which needed cheap driv replacements (the early escom machines ones had wiring mod on the board - which incidently sucked). This wire swap puts the diskchange signal in the right place.
The extra challenge is getting the drive ready signal to the drive.
This involved cutting wires 2 and 34. and connecting 34 from amiga 2 drive pin 2 (diskchange). a wire wire was then added to attach pin2 from amiga to a jumper pad on the floppy drive for the drive ready signal (this enabled full compatability with amiga software). i cant remember exactly which pad on the drive the wire went to, but maybe sometime i can pull the drive apart and take some pics.
There was a HD floppy driver (Hack) written for this drive but it was crap. you could format and fill the floppy and it read back just fine untill you removed the disk. then the floppy could never be read back.