After I worked everything out theoretically, I took the components and dry fit them. This was good because what looked good in my head and on paper simply wouldn't work in the real world. Don't cut or mount anything yet; you will regret it. Double-check the layout again before you make any cuts.

Xbox
At first I thought the X-mobo (Xbox motherboard) should go behind the PC mobo, but it wouldn't clear the side cover. Then I thought I should mount it under the top of the case, but that wouldn't work either. The connectors that attach to the X-mobo, the Xbox, and the PC power supply were causing the problems. I finally decided to make a mounting plate that would sit above the PC mobo and raise the edge to clear the PC components.

The placement of the Xbox power supply was a limiting factor because of the length of the power leads (unless you want to make an extension for these wires). Also, consider that the Xbox power/eject buttons should be somewhere in the front of the case.

GameCube
The GameCube game CDs are inserted straight from the top of the unit. To include it in the Boxx, you either manufacture a custom enclosure for the drive or leave the unit almost intact. I happily discovered that the system is almost 5.25 inches wide. A little work with a belt sander, and it should slide into place.

The controller ports are the only obstacle with the GameCube. They are attached with a ribbon cable that is not very common and is difficult to solder. The controller ports can be placed in front of the unit, so the ribbon cable won't require modification. The stock ribbon cable is barely long enough to fit.

PlayStation 2
The PlayStation 2 was a little tricky and yet very straightforward. I found that it could easily be mounted beside the 5.25-inch drive bays if the power supply was relocated. All I had to do was carefully mark out the cuts I would be making in the front of the box.

Nintendo Entertainment System
The 8-bit Nintendo was interesting. Its cartridges don't come straight out the top of the unit; they pop in and push down. I found that it could easily fit on the other side of the drive bays if I cut a hole in the side cover. I figured it would look cool that way, too.

Atari 2600
The Atari was the easiest. I had a junior model, so it didn't even have to be taken apart (except for rewiring the switches). It would mount behind the PC mobo with the power supplies.