Just about any projector will "do" 16:9, but if it is not native 16:9 that means letterboxing it with a black band top and bottom. That can affect the projector brightness required as when you letterbox the image on the screen the projector output is actually over over a larger area than the image itself. For example, 14'x8' is very close to a 16:9 format (which would be 14' x 7'-10 1/2"), but with a 4:3 native projector like that noted, to get that image you would actually be projecting a 14' wide x 10'6" high image and then only using the middle 7'-10 1/2" of that height. So the image brightness is actually based on the 14'x10.5' image size rather the smaller widescreen image size. Basically, you are 'throwing away' the projector output that represents the part of the image you are not using by letterboxing.
A major factor for the projector is the ambient light conditions, is the use only at night with no lights on the screen or is it at night but with ambient light from street lights or during the day? The BenQ projector noted may provide sufficient output for a fairly light controlled application but probably not for daylight use.
