For my electronics bench I built a small for factor pc (mini-ITX) in a cube shaped case and mounted the display on a arm clamped to the side of the desk to minimize surface area use. The PC itself I probably could make a shelf underneath to hold, but I have it shoved back into a corner that wouldn't really be of much use anyway(other than my soldering station and fume extractor, the bench surface is clear - I have my gear on shelves above it). Only thing takign up space is the keyboard and the mouse. The display on an arm allows me to pull the display where I need to see it, or push it up out of the way (and stack the keyboard and mouse on top of the case if I REALLY need the space). Nice thing about this is it is in every aspect a normal PC, not some specialized gear that may or may not run everything I need. There are even smaller cases available for standard PC motherboards, but after looking around, many have the same footprint, just less vertical height. I went with this one because it had plenty of USB ports, and two accessible slots to add extras (I have a card with 4 ports in it) so I have enough USB ports to connect the test gear and have cables to the work area to connect to Arduinos and so forth. Some things were not happy with hubs, which is why I went with the extra card. Plus I have another half of the bench yet to build, which will be for my other hobby, model railroading, and I have equipment for that which also needs USB connection. Same PC will serve both work areas.
Careful shopping keeps the cost down, and it's 100% standard hardware so I am at no one's mercy for any future repair, replacement, or upgrade.