The critical upgrades for an A1200, as I see it would be:
Cocolino or equivalent mouse adapter.
4GB CF-IDE adapter.
Those, with your Blizz will make a pretty awesome A1200 rig. The only other thing you might conceivably want is a CD drive. You can either mod a slimline laptop drive into your A1200 and connect it to the IDE interface, or seek out a Squirrel SCSI and a SCSI drive.
