If you're looking for a building experience that's going to be more difficult that you thought it would be every step of the way, then you've found it!

I present to you my rack mounted, rail sliding gaming rig.
She's very much due for some upgrades and cable management.

The case itself weighs 20kg (around 40lbs), the rails are an optional extra, I had to drill the mounting holes for the radiator myself, and even though it is devilishly long (666,6mm) it's surprisingly cramped to build in. I also had to jury righ my own external power button, because opening the front door of the rack to power on the PC got very old very fast.

Despite all this it has been the most fun I've ever had building a PC.
So fun in fact, that I managed to convince my girlfriend that we should rack mount her PC as well.

In the front we have 2x Lian Li 3x 5.25" bay fan mounts housing 2x Corsair ML120 PRO fans, 1x floppy disk drive for good looks, 1x random DVD drive I had lying around, and 2x Chieftec 4x2.5" SSD mounts each taking up 1x 5.25" bay (Blue one for backup, red one for daily data storage).
Next comes a cross beam with 3x Arctic F9 PWM fans, the radiator for my CPU AiO, and 2x Corsair ML120 PRO mounted to the radiator.

At the middle we have 2x RAM coolers scavanged from an old HP tower server that ran DDR2 memory.
In the rear there's the backside of an RJ11 connector for the external power button, and 2x Fractal Design Silent Series R3 60mm fans for rear exhaust.
The RJ11 connector for the external power button makes it easy to disconnect when I have to remove the case from the rack entirely.

Everything housed in the very robust Chieftec UNC-410F-B case.