Yes I knew there must've been a good reason for doing it this way. Your point now has me thinking of hanging (the fans that blow air into the tank) from the top of the canopy so that they run across the back. The back of the canopy is open so I would need to hang them from the top to run along the back.
I like the idea of placing the fan that removes hot air on top of canopy. In order to do this I must cut a hole into my light fixture. It can be done as I saw a DIY on this topic on Melevsreef.com.
You mentioned that the fans are on a timer. Do you have a timer that has inputs for multiple lights/fans? I have two metal Halide fixtures, a VHO
, a set of moon lights and fans, that requires at least 5 inputs. If not have you seen any that have multiple inputs for multiple fixtures?