Have you already bought the projectors? Also, I'm a little confused about what you are doing. Are you building a room where images are going to be projected on all four walls from four projectors? If that is the case, are you looking at putting an "island" in the middle of the room where the projectors will sit? If that is the case, and if you haven't got your heart set on the Panny, there are short throw projectors that will work - like the Epson EMP-400. A different choice may be Hitachi's line of ultra short throw projectors: http://www.hitachidigitalmedia.com/product.do?actionName=listProductAction&pt=6&pg=59 With the ED-A100, they would end up roughly 1.5m from the screen, so your audience would be in the center of the room. Hope that helps!