I have a DCN and three rats. They're so spoiled.
According to the cage calculator, the DCN should be able to house 12 adult rats, as long as you make good use of the space with extra hammocks and bridges and whatnot.
There are two homeless rats that are tugging at our heartstrings, but they look sick, so I'm not so sure that we'll adopt them, especially since one of them is so antisocial that she actually bit me when I tried to pick her up. But we have room for them if we ever decide to tackle something that difficult.