I’ve just discovered that you can use wildcards in the local ssh user configuration (~/.ssh/config)
host vm-* User virtual-machine-user ForwardX11 yes host board* User root
This lets me configure all my ssh access in a very short configuration. My virtual machines have a common prefix, and a common user – so that can all be sorted in one hit.
My target development boards are all identified by a board number (which correlates to its IP address too) such as board2 board3 board240.
Now I no longer have to type ssh root@board2. (Every saving is a saving!)