Thanks everyone, some great ideas. For reference, it is an Agfa Ansco field camera (not a monorail), so the rear extension can fold up to offer some protection. More or less, what I am hearing, is the basic idea of a insert that wraps around but does not actually touch the glass (or only the padding/felt) touches the glass. Does this provide enough protection from the regular bumps/knocks that walking would give? Perhaps the glass is stronger than I think but I just don't want to drive for 10-hours, hike for 5 and can't take the picture because of broken glass.