Another real-life they-can't-pocket-it example: I visited our local Pepsi bottler to examine their new SLC-500 and DeviceNet sensors/drives system on a new water bottling line. I was talking to the senior maintenance guy and asked him if he had a CD drive in his maintenance laptop so I could load a demo copy of our network configuration software.
He laughed and led me to the end of the hallway, where, under a tarp, was a small library book cart outfitted with their monitor, PC, power strips, and tool boxes.
It works fine for them; it's a small facility in one building and this will roll anywhere they need (well, except the mezannine they put the SLC-5/04 on. So they ran DH+ down the wall into a junction box !). The PC is an unremarkable 500 MHz model but you can get those for a song now.