As Hancock would say "good job" (film reference)
Surely it doesn't matter that it does not support ADF directly as long as the conversion process is quick and the tools support batch processing?
If I can make a few suggestions for possible improvement:
To get the price down further you could consider getting rid of the LCD. It might sound drastic but you've got a display device connected to the host computer!
You could replace the LCD with a default disk image on the SD card which would contain a boot program (different for whatever host you are running on) small, just a few sectors. The boot program would display the SD's contents using the hosts gfx on the Monitor/TV screen. It require some clever PIC code to convert the current SD card contents dynamically into virtual disk data on the rest of the disk. Disk image selection would be made by the host computer issuing particular floppy disk commands the PIC code can interpret. Once a disk image has been select it would remain selected until power off, or the eject button is pressed whereby it would default back to this boot disk image.
If you could do that it would be advantageous to make the PCB the same size as a standard floppy disk drive so that it would fit internally, the control interface could be only one button (Eject) used in a similar way to the Mac mouse (single click, double click, click and hold etc).
I am sure you could find suitable programmers to produce the boot menu program for each platform, if you open-source the API then communities would just write their own!
Just some suggestions.
Of course this idea is not practical for devices without a display.
Also the Amiga is not a good commercial target for this device, WHDLoad almost makes it redundant :-(
The Atari ST is much more of an attractive platform, commercially, for floppy disk emulation. However they have some coders who are creating their own equivalents of WHDload.
