Making a blimp for on-set/on-stage photography. I've got an idea that the lens cover would work well if rather than the conventional tube it was a box section (if it works I'll explain why). a 100mm box section would be ideal around 150mm long fairly heavy plastic and even more ideally an item which has an accessory flange for fitting/removal/to the body of the gizmo. Any ideas as to where such a thing exists sitting on a shelf ? plumbing ? air con ?