Honestly, if I log onto my job processor PC one more time and find that it's rebooted and been sitting offline for several hours or days I'm gonna lose it. No filter, plain lose it.
I understand the difficult logistics in having this trigger on the actual JP machine itself, but surely you can have an ADMS console based worker process which handshakes with the JobProcessor.exe process on the clients... if there's no handshake, ping the admins an email?