At some point last year, I decided to build one of these.
It works well! It does not have the niceties of some of the other projects, where you can see the disk image on an LCD or switch them up and down with a button. These things could be added to the firmware, as the software is very simple, and the hard part (emulating the drive) is already done!
I ended up having 10 boards made, since that is the minimum.
I thought I had the rest of the parts covered, except the SD-card slot is unusual- it's mirrored, so that is the most expensive part (not bad).
So I have plenty of parts left over and thought maybe some other fellow tinkerers would like to make one.
I have 9 bare boards left- $5.00 each.
Shipping only costs a stamp to the USA, and probably a couple bucks overseas.
I have enough of all the other parts for 2 complete kits.
(*out of stock, you can still buy kit without SD slot for $21.50 and get slot from Digi-Key)
These would be $25 each and I will pre-program the Atmel microcontroller for you.
Shipping is still probably a stamp in the USA and a couple bucks overseas.
I built and tested 2 of them, so I am offering one of them completely built and tested for $50.
Once they are gone, they are gone forever.
Let me know if you want one or have any questions.