As part of the restoration on my '64 Overlander, I had two sewer hose storage tubes added to my coach. They are sized for the 10' length of sewer hose - - if I had it to do over again, I would have insisted on the larger size as I rarely use my 10' hose, but nearly always find that the 20' hose is needed. Ace Fogdall RV installed them for me, and they were one of the more reasonable modifications. My next goal is to have a third storage tube added for my three telescoping flagpoles so that they won't be a continuing nuisance in the bedroom hallway. You can see the two tubes that are currently on the coach in the photo below (they are just behind the rear wheel.
Good luck with finding an acceptable solution to your problem.