If you use the silver remotes (or ones that have a narrow beam) you can make do with them in the same room. I had mine setup originally on each side of the tv, about 8 feet apart. I was able to aim the remote 3-4 feet outside whichever box I wanted to control and it was far enough from the other box that it did not hit it as well.
I have since upgraded to Harmony remotes and those things will hit the box no matter which way I point 'em. I then went to the "fancy" piece of carboard and stacked them together.