I don't know about you guys and gals, but I figured an interesting use of hurling 200 flasks of alchemist's fire was just a really slick attack method. I wouldn't stack the damage at all, but the damage isn't the point. How many flasks you throw isn't really the point. The point is creativity.
I envision a stack of these things sitting in a big open room, glamered so that they blend in with their surroundings. Some poor sap enters the room and WHOOSH!!!!...guy gets doused by the stuff, takes only 1d6 points of damage per round, and everything around him, probably in a good ol' 20-foot radius, is on fire. Nowhere to go without the risk of taking more damage. Pretty cool idea.
It's the same priniciple of a trap that tosses a bucket of burning oil on you and the surrounding area, just much more creative, especially if you don't know how to make traps. Honestly though, I think 50 flasks, or even 25, would do the trick just fine.