Wifi propagation in my apartment has been poor largely because of the back corner cable hookup. I'd been meaning to move the wifi access point to a better spot and find a router-only option to sit by the cable box when this article got me to actually start working on it. The author used a ~$150 mini-pc from China with two ethernet ports, which ultimately I think is the best option, but I was impatient (5 week shipping from most of the vendors on Aliexpress) so I figured I would cobble something together.
On Amazon I found a Celeron mini-ITX board with two gigabit ethernet ports and DC ATX power adapter, plus some RAM and an AC adapter.
There aren't many options for mini-ITX cases and I didn't like the ones I did find, so I just decided to make one with some printed parts and perforated aluminum sheet.
These came together in Solidworks over a couple evenings.
Not pictured - a lot of fettling because I mismeasured a couple things.
I made some light guides with t-glase, including one that fits over the power button so it lights up. I painted the rear surfaces of the guides white in an attempt to direct more of the light in the direction I wanted but I'm not sure it helped much.
In addition to the power and HDD LEDs, I attached some leads to the RJ-45 activity indicator pins and routed them to the front for extra blinky.
Everything fits about as snug as it can be, but should have thought more about cable management ahead of time.
I don't have a bending brake but managed to make this work using a metal ruler and piece of 3/8" threaded rod.
For software setup I started with Ubuntu server and followed this guide for the most part. I haven't done any bandwidth testing yet, but it seems to be working great.