I don't project larger chromes either, but I do love to slap 4x5's down on the light box from time to time.

I also found a shop that sold (old stock) of a black matt surround and plastic sleeve. They are re-usable.

I have a few 4x5's mounted that way and occasionally tape them up in the window of my office, usually in the dead of winter, to get oh's and ah's from people when they stop by to check them out.