Thats a nice bag and now on my list, however just looking at the Mk 5 which also looks great, I'm wondering if the Mk 5 might be worth looking at in light of the fact the price should come down significantly.
To be honest I dont have any problems with obtaining second hand Ortliebs in decent condition, so all you 'Early adopters' who are going to get a Mk 6 consider giving a good home to your old Mk 5 friend...