2.5" IDE

[Ilwrath]

Correct...  My A1200 is running a 2.5" toshiba drive.. out of... err, an old Toshiba work was scrapping.  

Try to find a real C= mounting kit for it, though.  Otherwise, you'll have to improvise a bracket (easy) and find or make the smaller laptop-size IDE cable (hard)

[Ilwrath]

the cable to connect the drive I suspect is easier to find than the more powerful PSU you'll also want (with likely an accel, too).

Yeah, the A1200 power supply is a little feeble.  I just took one of the older, heavier A500 power supplies (from a dead 500), though.   (Even better to take would be a 3rd party heavy duty A500 power supply.) They should be fairly easy to find.  I remember calling no less than 10 parts dealers around here, though, looking for that laptop IDE cable...

BTW:  Is National Amiga still around?  They were good guys...