How about the good old RAD: device? You'll need to edit the MountList and change the HighCyl number to 79 so it has the same amount of tracks as a floppy drive.
I use Tracksaver (aminet disk/misc/tsgui.lha) to write the ADFs to RAD: (or to a physical floppy for that matter). It has a nice GUI and works with anything from Workbench 1.2 and up.
And because it's the RAD: device, you can even boot from it after you've unpacked the ADF to it.
