I've done a little bit of looking, but most of what I've found has been way too big or way too small for what I need.

I've got a 6'x8' HFGH that I'd like to find a fan / louver combo for. Hopefully one that won't take up too much space in this already cramped little greenhouse. It needs to move about 600 cfm, and be small enough to fit in the space at the gable end of this little greenhouse. Anybody have anything they'd like to recommend?