AbdulAlhazred
Legend
I think 4e handles this problem fairly well. WotC doesn't provide many examples of this now, but a couple dozen Orc Berzerkers are a perfectly reasonable swarm for a 20th level PC.
Personally, I think we've seen limited support for this type of enemy from WotC because WotC is saving that kind of encounter for a mass combat supplement.
-SS
I think running 24 orcs on the board at one time is more like DM nightmare. I'm considered pretty darn fast at running monsters (I can do all the monsters turns in most combats in less than 2 minutes with 8-10 monsters usually). It might not be THAT hard to figure out what to do with 24 orcs (charge of course, what else do orcs do?) but then they'll have various different conditions on them, ongoing damage, etc before long. Doesn't sound fun. 24 minions? I'd have no problem with that, but full monsters, bleh!