Not exactly on topic but there used to be a utility (with TSR driver) for MSDOS that bypassed the floppy controller and allowed one to format, write and read custom disk capacities.
The maximum capacity depended on the psychical abilities of the disk drive.
I remember getting really excited when I formatted a 1.44MB disk to 1.9MD and then compressed it to get like 3.5MB. It wasn't very practical and I think it was kind of slow.
A quick search on goggle found "HD-COPY — Fast diskette copier and high capacity formatter." On this site:
here.
I don't know if it's the same utility but I wonder if something like this could be used to write and read Amiga formatted disks on the PC?
Just a thought…
I think it was the 2M utility... Just for fun I'm formatting a disk to 880k I type this. I wonder if it'll be able to pull it off 
