I'll have to admit I've never seen a ceiling fan in an outdoor space before, guess I didn't think they'd be very efficient. I wouldn't mind some indoors in our house, but with absolutely minimal ceiling height its not something I'll be doing....I hate getting whacked by other people's fans when you forget about them and raise you arm, or child!:oo: I hear they are really good for pushing warm air downwards with a woodheater going? I'll stick with pedestal fans etc, not into air conditioning myself.
Back on track, I'm inclined to lean towards Mr Fixit's solution, that of preventing the build up of hot air to begin with. Can you fix some sort of false ridge cap all the way along, with an air gap underneath?
Cheers,