The cheapest way to do it is with these products (this method involves no hacking of the A1200 desktop case):
4-Way Buffered IDE Interface:
http://amigakit.leamancomputing.com/catalog/product_info.php?products_id=532(Mounts internally in your A1200)
3.5" 40-PIN MALE TO FEMALE IDE CABLE (5 INCHES/13CM)
http://amigakit.leamancomputing.com/catalog/product_info.php?products_id=550(connects to the 4-way buffered interface, feed the cable between the two halves of the A1200 shell with only the socket visible)
External IDE CD drive case
(We have a few of these cases that can be use to house and power a standard IDE CD drive- you will need one more of the above cables to mount a socket at the back of the CD drive case)
3.5" Round IDE cable to connect the A1200 desktop to CD drive case
