Amigakit sells a buffered ide adapter that has 3.5" ide connectors on it. You could get one of those and run an ide cable out of the back of your 1200. For power, you can use the hardware from an external usb harddrive, or splice into the a1200's floppy power connector. Depending on your other hardware (accelerators, etc..) the a1200 PS may or may not be able to keep up.
Other options are:
* subway usb card, then connect any usb cdrom drive
* slimline (laptop) cdrom, and an adapter.
