I remember a campaign where I played, the very first quest involved the slaying of a rather large rather old dragon. Or so we thought.
Village A accused the dragon of killing villagers and eating livestock. Village B we found out, had no such problem. But we found this out a while later.
After the assault on a rather large goblin camp, and, the killing of one troll, (Gosh that was hard. I remember it. A bunch of level 1s ~except the rogue, he had leveled~ facing off against a troll was nasty. Mr Troll ate me, the mage. (I was brought back! Very kind healer was nice enough to bring me back)
Anyhow, we finally found the dragon hole, gritting our teeth thinking our DM was totally INSANE for pitting us, a low level party of nobodies against such a beast. Instead of eating us though, this big huge green dragon welcomed us actually, inspite of being the evil brute he was. He was really very old, increpit one might say, but, still very powerful. The dragon informed us he had no wish to fight, he knew why we were there, and, informed us it was all a misunderstanding. Village A had stolen something from him, and, he wanted it back. We found out that both villages had made a deal with him a long time ago, that he would protect the villages from a big red dragon, and, since some creep had come into his cave and stolen something, Big Green was letting Big Red enter his territory and attack Village A. Big Red however, felt the need to try and oust the big green dragon, and, had used illusion to make people think it was the big green dragon. Ok... I hope nobody is lost here, it's getting complicated.
Long story short. We went to Village B to find a Sage who could divine who the thief was, and, when we found out who, we had to go track him down. (And got our selves into a horrific battle with a gnomish mage thief who went a little crazy with the fireballs and the stinky clouds.) We recoved the little statue the dragon wanted, and, returned it for him. He gave us a dagger, +2 that slays kobolds by touch. Quite a powerful item really, but, we had gone through a lot of trouble and we really deserved it. He promised us something even better if we would take care of the red dragon for him. Not kill him, just teach him a lesson. That began a long trek high into the mountains and we had to place an explosive ward on the entrace of his cave, which we finally found after a lot of searching. Spoke the command word, and BOOM! Tons of rock sealed in the pesky red. However that boom also attracted the attention of some really nasty ogres and a whole bunch of kobolds and goblins that hunted and brought the dragon food and things it wanted.
Ahem. Anyways. Our reward for that was another artifact. A sling that fired rocks and never ran out of ammo, and, it had a 1/100 chance of when a rock was fired, the rock would turn into a 6D6 fireball.
So you see, it is possible to interact with dragons. You don't need to make a scenario to kill them, although that could be one (Stupid) option. And it is possible to provide actual artifacts and powerful items, but only if you make the scenario hard enough to warrant them as a reward.
Sorry if the above recollection seems a little broken up, but, I can't recall every little detail that happened in that game. By the time we were done with that whole adventure, everybody was around level 3 or 4, except our rogue who was level 5 because he pick pocketed everything he got his hands on and got lots of experience.