I have a PC floppy internally that was converted to an AMiga high density drive by one of the tech guru's at our user group in 1997. Its a Panasonic and i have no idea how he did it. There is no circuit board, no software it just plugs in and works..with NDOS game floppies as well. The same guy that has this page
http://members.iinet.net.au/~davem2/amiga.html did it for the cost of the drive!