Well, I kinda screwed it up.
Remember how I "de-located" the cart slot? Big mistake. I tried desoldering, but it wouldn't budge even slightly. So I ended up hacksawing, ripping, twisting and dremeling it off. Now I have this metallic, probably conductive dust on it. I think I've got most of it off but I'm worried about it staying in the cracks.
I also figured out how to do a docking port. I'm using standard double headers and part of a floppy or maybe IDE cable.
No casework, because my new batch of liquid ABS isn't ready yet.