Well I had some time after all so here are a couple of pics...
Grow Box support equipment. As you can see this is an attic somewhere in the world. The blue thing is a Fantech blower connected to the box (exhaust side) via an insulated duct. In the foreground you can see the fan rheostat and the switchable ballast for the 400w light.
The picture below is a view of the box with the door leaning up against it. The door is completely removeable so that access to the interior is unrestricted.
More later on the actual construction process.