I know these types of builds are a dime a dozen, but here's my very own OG Xbox build: Midway.
I caught the SFF bug after seeing videos of small cases like the Velka 3 and seeing the Ghost Canyon NUC rumors and decided to do my first SFF build in a custom_mod FX stl 4.7L ubc. Then I discovered console sleeper builds and knew I wanted one.
I tried doing a metal base bracket like Tech By Matt, but kinda failed since I lack the skills and tools. Plus my parts were completely different, so yeah.
The most I could afford at the time was a 1070, so LTT's build still has mine beat but I decided to at least get a bigger PSU so I'll have more headroom for upgrades later on (and because I have a 400W Delta PSU in my first SFFPC and the coil/fan whine on that is horrific, so I don't want anymore of that).
The PSU is a 500W Pico-Box PSU that is powered by 2 230W Asus power bricks, which I hope means I won't be stressing it too much. And because the PSU's manual says to keep it cooled when using more than 180W, I had all case fans installed as intake to make sure there's always cool air blowing over it. Since I left the I/O shield out (couldn't fit it), I figured there'd be enough pressure to exhaust out that way.

So about the temps:
At idle
CPU: About 36 degrees C
GPU: About 34 degrees C

Using XTU and Furmark Stress Testing together for 3 hours
CPU: About 85 degrees C (CPU fan doesn't sound very loud at all since the side fans can still drown it out)
GPU: About 74 degrees C with fan speed staying around 65%

This build is used for my living room gaming PC with a focus on couch multiplayer, so all my local multiplayer games are installed on this machine as well as everything that is a Microsoft IP. And of course, it just makes sense to pair an OG Xbox build with Hyperkin's remade Duke controllers.