I'm not sure how I managed this, but I swapped out my Color Classic motherboard from another one I had in my parts bin, and it turns out to be a mobo from a Color Classic II (aka Performa 275), according to the Gestalt ID (reads as "83").
Anyway, it's up and running smoothly, with 36 megs of RAM and an external 2gb SCSI drive. Now I need a way to get it on the network.
So, if you've got a card that'll work in this machine (I'm a little confused as to what type of card I'm actually looking for - LC PDS or Comm Slot 1 or 2?), I'd love to pick it up!