I've had this lab for a few years. It's based on some old hardware but it's rugged and it's stacked and it's good to go at a moment's notice.
The whole thing is housed in a 5U Pelican Hardigg surplus TACLAN case. It still had sand in it when I got it. I had to blow it out before mounting my gear.
(Click the images for a closer look.)
FRONT
The top 2U are a half depth drawer where I keep cables, SFPs, screws, tools, a USB Crash Cart, and assorted things I might need on the road.
The middle U is an HP DL360-G8. It's got two 12 core 2.0 GHz XEON E5-2697v2s, 284 GB RAM, eight 500 Gb SAS drives, and an HP P421 SAS controller. It has two 460W hot swappable power supplies and is fully loaded with fans.
The bottom 2U are an HP D2600 Smart Array SAS controller with twelve 4 TB drives.
BACK
The top U is a Cisco Catalyst 3750G switch.
The second U is a PDU.
The third U is the back of the DL360
The bottom 2U is the back of the D2600.
CASE
NOTES
I'm running the HP DL360 specific ESXi.
It goes, and it goes. I've run 2 dozen virtual machines including AD and Linux servers, an HR server, a RADIUS server, an SSO/MFA server, and a number of network inspection and threat hunting appliances. The engineers at the company I was working for at the time would remote in to my lab because it was more performant and more reliable than the company lab.
It weighs a ton but I can paletize it, load it (using my tractor or a fork lift), and hit the road with about 30 minutes notice.
"Lab" is a misnomer. I was running a lab for an adjacent product but the real grunt of this box was used for real time breach detection and hacker hunting where the box needed to be plugged directly into the network it was analyzing. I was very VERY good at detecting breaches. I met a group of the operators of APT1 and they knew who I was. Heh.