There are short throw projectors and long throw projectors. Nicks recommendation of looking at ProjectorCentral's reviews of various HT projectors, and then using their calculator will give you an idea of what projectors can accomodate that distance.
Big is not always better, especially if a quality image is important. Room conditions also play a factor, as does screen material.
My Z2 is a short throw design, meaning from a short throw distance you can achieve a large image, I"m at 13ft throw. Just make sure before you buy the projector, check the calculator and make sure you can achieve the size screen your wanting from that throw distance. Zoom helps to achieve this, but it is best to try to stay near the lower end of the zoom spectrum.
Randy
