You may look into stands made for music equipment (large speakers and whatnot) with that kind of monitor arms. You can then put a VESA arm on it to hold the monitor. You may be able to put casters on the bottom also, so it's easy to move, but that depends on exactly how you set it up. It needs to be absolutely stable so it wouldn’t fall on anyone.
You could get something with a desk clamp mount, then just clamp it onto a side table or some other heavy/sturdy furniture. It would just have to swing out to the side then could be pushed back when not in use. I have a friend who uses this set up and just rolls in next to the table and pulls the monitor over. The thing you clamp it too does have to be heavy enough that the monitor won't tip it over though.