I've mostly used TrippLite and Dell rack KVMs. Just the standard ones that have a 17" monitor and rails so I can see what's going on with a server that is down.
The scope is to check on servers that are in a critical state so using software based solutions like Multiplicity I don't think would work, since the machine isn't booted up to be able to load the software, right? Unless I'm mistaken somewhere on that...
What KVM are you using? Got any recommendations before I buy something like this:
http://www.tripplite.com/netdirector-8-port-1u-rack-mount-console-kvm-switch-17-in-lcd~B02000817/