Bitlynx PM'd me that he had been away for a weekend so couldn't fix the rig when it went down, and offered me 12 hours extra for the trouble, very stand up thing of him to do!
Again, terribly sorry about that. Very odd that rig appeared up and computer had network connectivity. If it happens again, I'll need to see about setting up a monitor to detect that condition. I wonder if giving renters the option to reset cgminer would be a good idea for some self help troubleshooting.