I wouldn't be suprised if it was one of the larger limo companies who operate around here. If you can get an old hearse, a fire engine, a Ford Gran Torino or even a stretch Hummer then I'd expect nothing less than Fred's van.
Well I thought that, and I have found a company down south that have 2 they hire out, but I can't find anything about the one I saw up here, other than someon's blog saying they have seen it!