i dont know what you mean by "glass ceiling" but where i train ranking is determined by both time and ability. you cant go for another rank without doing a certain amount of training time, and without having a certain amount of ability. so if you put in the hard work, it is possible to pass who were previously your sempai, as i have myself done.
oh and just for interests sake, we dont have a formal grading day, instead when you feel you are ready for a grading you tell the sensei and the grading takes place in small increments at the end of class for however long it takes. if a section of the grading is not satisfactory the grading will be stopped for that day and continued later..... i dont believe there are any failed gradings, just gradings that take a lot longer.... so far i think the longest has been over 2 weeks. oh and there is a student who started his grading and has now dissapeared from the dojo halfway through without finishing it. we haven't seen him in months.