Keith was my first thought too. A couple of folks did... Daniel Blanchat being one of them and he did a couple of Mule shows in the area during that time period. I don't know if this was his though, but that's a starting point.
>>>> Thanks Page. Would you happen to have any contact info for Daniel?
FWIW I believe this same rig was used at another Mule show shortly before the Tradewinds' gig.