I built one back in college: https://63towuxu569fy07zrhhj.mnutt.sandcats.io/2006-07-23%20... , https://63towuxu569fy07zrhhj.mnutt.sandcats.io/IMG_3628.jpg

I didn't do a whole lot of planning for airflow, but it seemed to work ok. The back was more open than the front. I built out a metal frame that was inserted into the box, but afterwards realized that I probably could have just bolted the rack mount rails to the wood and called it a day.

Unfortunately, it was kind of big and unwieldy for keeping in an NYC apartment. I wouldn't be surprised if it's still sitting in the Brooklyn apartment where I abandoned it during a move.

I wished I'd taken them. I know one of the other people did (I will ask them), but it was 97ish and I didn't carry a camera phone with me. It was quite nice and properly stained with bits of metal for securing the servers with slide out shelves. The did leave decent area for air flow.