From the update:
After getting some feedback on what people would like from the Dungeon Creators, we have decided to double the size of the detailing area compared to the last pic shown in update 4.
This will be included for all 25mm and 30mm Dungeon Creator stencils, EVEN those going to backers at the lower levels.
Even with the enlarged size, it will remain a standard choice, and the same price as the others, but will likely be a higher price when they go for retail sales.
Having said that, we still did not have enough room to fit in all the goodies we wanted to, so expect to see a "Dungeon Detailing Pack" added to the standard design list before the end of the campaign.