Something I tried finding too. I bought some new storage boxes and the sleeves were pathetic, they were sharp and tight, and marked up some of my discs. I have ended up modifying/cutting some of my old sleeves, and then inserting the plastic rod/bar into where I have cut:
If you have no spare bars, I guess you are unable to do what I have, so I'm curious to know if you found any stores selling the sleeves with bars? I don't want to spend another few hours cutting out more sleeves lol.