I have a client that insists on having 2 4-gang switches stacked on his back patio for a plethora of outdoor lighting. I've never seen a 4-gang water tight cover but recently in Maui I saw a large hinged cover that would work. It was on a commercial site but was being used exactly the way I intend. It looks like an outdoor bubble cover except it was probably 1' X 2'. The part that went against the wall had the neoprene type of seal built onto it and it fastened against the building with screws.