Is there a (or has anyone made a DIY) portable keyboard, monitor, and mouse?

I've been looking for something that doesn't appear to exist: a portable keyboard, monitor, and mouse (KMM).

Problem description: You need to work on a headless computer, or one whose KVM monitor, etc., has died. You don't want to carry around a full size keyboard, monitor and mouse.

Proposed solution: Device with a laptop form factor, with a cable snake or inputs for video, PS2 mouse and keyboard, and USB, also for keyboard and mouse. It would fit in a laptop bag, and you could take it with you on site, connect it up, do your work, and unhook it.

I've opened up a few old laptops to see if I could access any connectors, but I haven't had any success.

Has anyone built or used something like this? I think it could be a useful techie tool.