From what little insight I could gain, I agree about the hardware problem. The customer I was talking about was nervously trying to find a reliable supplier of motherboards with ISA slots and parallel ports.
I really love the nostalgia this kind of hardware stirs in me, but I am glad I do not have to deal with that kind of trouble. (A few years ago, I read on another forum about an IT guy getting a call on the weekend from a desparate customer looking for an HDD using some standard that predates non-S-ATA... MFM, I think?)
Luckily for that guy, someone has made a MFM-to-SD-card with arbitrary command and geometry transformation recently, it it has turned out to be great. There are MFM-to-SCSI and even SCSI-to-floppy interfaces. The great thing about SCSI in the middle is that it's the same protocol supported by systems today so you could then just convert using generic hardware and software available right now. The system on the other end is none the wiser and thinks everything is still the old interface with the old parameters.
I really love the nostalgia this kind of hardware stirs in me, but I am glad I do not have to deal with that kind of trouble. (A few years ago, I read on another forum about an IT guy getting a call on the weekend from a desparate customer looking for an HDD using some standard that predates non-S-ATA... MFM, I think?)