tl;dr I built a HTPC in a metal toolbox.
I've seen some of the builds in things like briefcases and NES shells. I wanted to do something similar, but I wanted it to also be my own. I had a few ideas, many of which proved to be somewhat pricy. I wanted something I could work with where I wouldn't feel like I'd wasted a bunch of money kludging it up. I solicited suggestions from family, friends, and coworkers who all proved marginally useful at best. It wasn't until I took a trip to the local resale shop that I found this little critter tucked away in a back corner of a poorly-lit room. Seriously, you should see this place. It used to be a sausage shop, and now it's like a big indoor rummage sale. But I digress... It had a sticker that said $5, but everything was 20% off that day, so I paid a full four dolla'.
Before this project, I had only done a wee bit of metalworking. Most of the work was done with a drill and a Dremel. For the Dremel, I used a metal cut-off wheel for making the large holes, and a grinding attachment for smoothing rough/sharp edges and removing burrs. I made numerous mistakes along the way. I measured the I/O shield incorrectly (twice), drilled the holes for the motherboard standoff in an incorrect pattern, drilled the PSU mounting holes just a little off and started the ventilation holes for the PSU intake fan in the wrong spot, resulting in the odd shape/pattern seen in a couple of the pictures. I originally wanted to have both a power and reset button, but one of the two switches I got from my dad was a momentary off switch, rather than a momentary on.
As far as parts go, I primarily went for inexpensive items. I didn't want to wreck anything expensive if I made a serious error. The PSU and RAM I had leftover from upgrades. I've used SSDs before, but this was the first time I've used one in conjunction with a CRT monitor. It's just an ancient thing I had lying around in the basement, which just happened to be where I was working anyway. I was amused once Windows had installed because it would boot into Windows before the monitor had a chance to "warm up" and actually display anything. The "case" had a nice little space to tuck away excess cables, which worked well.
After finishing everything, I fired up Prime95 and let it simmer for 60+ minutes. Considering that it has no dedicated ventilation besides that for the PSU and was running the stock CPU cooler, it seemed to run cool enough. I couldn't get a good reading on idle CPU temps (128C? I think not, SpeedFan!), but it didn't go over 52C under load, with the temp inside the box sitting around 41C.
I learned quite a bit from this experience and hope to take that knowledge into some similar types of builds in the future. This one is obviously meant to be at more of a HTPC level of functionality, but I have some ideas for integrating some higher-end components for a more gaming/enthusiast level of performance.
As a final note, I do plan on selling this, so if anybody is interested in purchasing, PM me.