Thanks for posting this, Reinhold. I just called up my photo guy and told him to hold a 3 1/2" #6 Packard for me. (6 1/2" square overall) $20, sans bulb or tubing. I will try a similar front mounting system as you have here, though I think I will have to modify it a little more because I have a couple of process lenses that turn to set the aperture, which might not work too well with a huge Packard on the front. Maybe a swing-arm kind of arrangement which would allow me to move the shutter into place after composing and setting the aperture. I've got a couple of little hinge thingies that might do the trick. I will post pictures once I have it set.