Cyrus Con taught me that it is still possible to have a "huge" player group and have a mechanically sound game that flows well. We had 10 players, plus animal companions, and the pace of the game was just fine.
We kept in mind that there was a bunch of us and we had to keep it flowing. What helped has having the Cyrus Con "rules" written on the white board.
- Roll your Damage and to-hit at the same time.
- Know your action before your turn.
- Don't ask me how something works. Look it up and ask me if you need a clarification.
We tended to also take simultaneous turns. If the fighter was rolling his attacks, there is no reason the rogue couldn't do the same on a totally different target at the same time- the actions wouldn't affect each other. Additionally all initiative was kept track of on the white board so everyone knew how soon they were coming up.
In college I think the biggest group I DMed for was about 15 people. You just never said "no, we're full" back then. It looks like you can still run for a very large large under the Pathfinder RPG rules, but I still have my preference for my normal sized group- 4-6 players. Fewer players allow for more one-on-one time with each PC and increases my ability to give them each spotlight moments