Oh man…back in the day ('92ish), Blackburn used to make a cage that held a huge convenicen store WB. Worked great for trips to Moab. Would be just the ticket right now for long, solo rides so I don’t have to stop at stores to refuel. They should reintroduce it for gravel riding…would be perfect!!
http://www.retrobike.co.uk/forum/download/file.php?id=180483&sid=9eb0f52d713d889c2ee5913fb1be96c7
ETA - I don’t know why the pics won’t post. tried two different ones…follow the link to an image of the cage.