Dan, many people let their tribes get to be 90, and when possible even larger. Personally, I always grow my tribes (have multiple slots going) to be the highest possible and love to watch the late-in-the-game actions.

At the point where you have solved all the puzzles, and you are no longer trying to just keep your village alive, you can try out different challenges with them. For instance, although I might select a few that I watch a little more closely, I may try to make an entire village of 90 into master doctors, or farmers, etc. Some people try for entire villages of all blonds/redheads/brunettes, etc. Some for all Jack of All Trades. and so on.
Keeping a large tribe isn't that hard once you've gotten past that breaking point of survival. Some of the funniest things happen when you have a lot of villagers too! In fact, I'm sure that you'll have plenty of stories to share with us if you decide to continue to let your village grow!
