[Tfug] Use laptop as external kbd/monitor?

[Angus Scott-Fleming]

Does anyone know of any way to use a laptop as an external keyboard+monitor for 
systems that are running headless and can't run VNC?  I  have a number of Linux 
boxes running stripped-down distros as firewalls or as NAS-devices, and it's a 
PITA to have to lug around a keyboard and a monitor to get to them when I need 
to troubleshoot beyond what I can do an SSH session.