I think I have one in the loft. It's certainly slim line and is external (in a housing). I used to use it with my A1200 with the IDE cable trailing outside the case (think I used Allegro CD). Sure I bought it originally from Amikit or somewhere. Not sure I have the power supply adapter for it though. If it's of interest to you drop me a note and I will take photo's etc.
Cheers
John