hi illumiquest

i can't really help you on the packard shutter idea
but reinhold, here on apug .. the person who makes
the wollaston lenses is working on a shutter project ...
i don't know how huge it would be, but he might be able to
custom make you a large one, once he gets the kinks out

http://www.re-inventedphotoequip.com/Site/Shutters.html

good luck !
john