[mlangsdorf]

For d20 games, one thing I've seen is the idea of minion HP pool: if you have 100 crewmen with 5 HP each, then their HP pool is 500 HP. Damage done to the minions is subtracted from the pool, and for every 5 points of damage done, a reasonably appropriate minion dies.

This simplifies a lot of the book-keeping, because you don't have to record individual HP. It's a little weird when the wizard hits 4 people with Burning Hands for 3 HP damage each and two of them die, but meh, on average it's appropriate.

With that minor modification, I'd be willing to try a large combat in a d20 game. You can roll attacks and damage by the handful and there aren't any rolls that switch back and forth between attacker and defender, so it's a pretty good system for large individual contests.