I think you’re right that Joanna’s current record won’t stand, but nobody has broken it. Private servers don’t count. They used BC exp values, and crazy dynamic respawns.
That being said I’d expect a record around 4 days /played. Now if you played for 18 hours a day, and played at a 4 day pace, you would hit 60 on your 6th day playing. So theoretically it’s possible, but I don’t think we’ll see a week 1 MC clear. Several guilds will have it down week 2 though.