I agree about the SE case, of the square fronted compacts, I find it most appealing because it was of the first generation of truly expandable Macs and is a perfect match for the original Radius FPDs and TPDs that were the backbone of the PageMaker DTP revolution.
I have to disagree with you about the curvy Classics though, the curved face is absolutely functional, it is much stronger, resisting punch through and cracking than the square faced compacts.
If you're thinking about a tray or cartridge loading CD Hack, the Classic's case wide FDD recess/dado (woodworking jointery term for a slot, usually implemented for a shelf or divider support) makes it a perfect fit for your choice of drive. With a little jig work and a router, you could widen the recess to fit either Optical Drive.
In the case of the tray loader, I'd be tempted to file the tray front to as thin an opening as practicable and then run the jig/router combo across the face of a second Classic front bezel to create a matching curved applique for the face of the tray.
just my thoughts . . . }
. . . per request.
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