I have been using this bag : https://www.polarbearcoolers.com/product/original-48-pack-soft-cooler/
since 2012. Yes the zippers tend to get verdigris but every time I am back from a trip I just spray some silicone based spray such as
and the bag is still going strong !
Its very large and takes in a Nauticam Housing for a 7D with arms and strobes all well tucked in. Also works well as a rinse tank and protection for your housing/camera.
One of the image shows the verdigris on the zipper. But all works well.