I recently obtained 6 Macintosh SE's, and I have evil plans for them all, BWAHAHAHAHA!. Meet my first victim, MACSE.
This picture is just a mock-up. The ATX hole is cut, and the motherboard is mounted, but the powersupply, and floppy are just shoved in there, and the blacklight is just to give me an idea of what it will look like, I'm not really going to use that 12" light in that tiny case.
This is a side view so you can see the ATX backplate. I originally cut holes for each interface, but decided no matter how much I'd work on it, it would still look like crap.
Here's a look into the unit to see how I mounted the motherboard tray
I used hot glue to mount the metal tray to the plastic standups in the rear of the case, this gives backside clearance of just over half an inch.
Incidentally, the tray is an old 486 motherboard tray that I cut to size and used my dremel to make new holes for the ATX standoffs. A couple of the holes were a little too big, so I used hot glue to secure the standoffs on the bottom side. It was a very shoddy job, but the end result is just fine by me.
Any questions?, email me: firstname.lastname@example.org