This is a project that I finished many months ago but I thought I would try to contribute...
What I did isn't exactly a case mod but is similar in some ways.
I took an old centipede case that someone in the neighborhood was throwing out and put my computer in it. I mounted my monitor where the old screen used to be and put the computer on a shelf I made so it was easily accessed through the coin door. Probably the biggest thing I did though was mod the trackball and fire button on the control panel to act as the mouse movement and left click. I was going to install MAME(arcade emulator) on it but never got around to it. It is now sitting empty in my room without anything in it because I got tired of having to sit on a bar stool to use my computer. Hopefully I can someday get hold of a crappy computer and get MAME running on it.
Here are some pix. I don't have very many detailed pictures because this was done several months ago...
The front... I forgot to mention that I made a keyboard tray for it too.
Close-up of the side art. The case isn't in perfect shape, but good for being 20years old and found in the trash.
Kinda ghetto but when the door is closed you don't see it. That my stock HP case. haha.
Control Panel. Its actually very comfortable to use. I would almost prefer it to a mouse if it came in a smaller package.
Monitor mounts (taken from the inside)
The Trackball labeled and ready for soldering to the mouse PC board.
The donor mouse PC board that I used to solder the trackball to.
Thats pretty much all I have...
If someone wants me to be more detailed on how I made the trackball and fire button control the mouse or anything else I would be happy too.