Packard shutters are still made. See:
http://www.hubphoto.com/packard-shutters.htm

  Its hard to find old shutters, you might try places like
Stephen Shuart or Midwest Photo. A good idea is to mount a
single large shutter with a lensboard adaptor on it. That
way you can use any lens within the clear aperture of the
shutter. I have a No.5 Ilex Universal set up this way but it
can be done using a Packard shutter. My adaptor works for
5-1/4 inch square boards as used on 5x7 Agfa cameras but I
also have an adaptor board for 4x4 inch Anniversary Speed
Graphic boards and most of the barrel lenses are mounted on
these. I also have a small iris diaphragm clamp on a 4x4
board that allows the use of enlarger and similar lenses
mounted backward for macro work. Iris clamps seem to be rare
but I've seen a few for sale.
  Packard shutters can be front mounted but its usually
easier to use a conventional rear mount on an adaptor board.
Its not too difficult to make an adaptor for 4x4 lens boards
even with hand tools.