What I really want is for my state (SSD, RAM, maybe the CPU, but probably not the GPU) to be easily detachable from my human interface devices (keyboard, mouse, display). I want to be able to use a desktop in one place, then unplug a small unit which contains the aforementioned state (i.e. the equivalent of a sleeping laptop but with no keyboard or display), carry that someplace else, plug it in to a different set of HID devices, and pick up exactly where I left off. And, of course, one possible set of HID devices would be something like a present-day laptop so that I can continue working while en-route. But there is no reason why the business end of a computer needs to be in the same enclosure as the HID, and a lot of reasons why it should not be.

I can do much of this now with a USB3 SSD, but the problem is that there is no way to "sleep" such a configuration. To change locations I need to shut down in one place and reboot in another.