Do you have an self sufficiance? No offense, but all it takes is this. Cut out a circle in the location of you liking. Attach the fan there in some fashion, glue, screws, w/e
Run the wires into the console to a voltage source and solder a little and you good...not brain surgery.
The only advice I can give is this. You can install a fan header to make your install go a little smoother.
Add Front Fan Header To 360 Motherboard - Scenyx Entertainment Community
You can instead of hooking the fan up to 12v, you can 9v the fans, 7v, and 5v the fan/s if you don't want it going full throttle all the time.
You can add a switch, to alternate the fan between 2 different voltages.
It isn't complicated really.