Although it wasn't the intent, the ol' Age of Worms AP in Dragon Magazine was actually a pretty good dragon-slaying AP. They weren't in every adventure, but where they were peppered in, they were each different from the others but still a dragon battle.
The next adventure was a battle against a single adult dragon.
A couple adventures later, you find that dragon's lair and battle it's three children. In play, a fight against a single adult dragons is a lot different than a fight against a trio of younger ones.
At one point, there's an invasion of dragons. There's some dragonswarm business going on in the background and a number of one-on-one fights with individual dragon "officers."
Finally, in the penultimate adventure, you battle a vampiric silver dragon (who you might have believed was helping you) and *the* dracolich.
Like I said, it wasn't even the point of the AP, but the number and variety of dragon encounters, from fingerling swarms to roleplay and betrayal to epic lichiness, was great.