If you really want a classic adventure to convert to Eberron, I would suggest the "U" series, starting with Sinister Secret of Saltmarsh. The party investigates a haunted house, only to determine that it is not haunted, but is a cover for a smuggling operation. Investigating further, the smugglers are running weapons to the nearby lizardfolk. The town council panics, and assigns the party to scout out the lizardman camp.
As it turns out, the lizardfolk are not a threat. What is actually happening is the lizardfolk have been pushed out of their territory by a tribe a sahuagin, who actually are a threat to the town. They are trying to purchase arms and make alliances with various aquatic races in order to deal with the sahuagin threat. The party may or may not figure that out.
There are two obvious ways it can go. The party figures out what is going on before they slaughter the lizardfolk. They can negotiate an alliance between the town and the lizardfolk, but only if the party pays compensation for every lizardfolk killed by them up to that point. They then recon the sahuagin lair with the assistance of the lizardfolk. Otherwise, they only figure out what is going on after they kill all the lizardfolk, and have to do it without the lizardfolk's help. How well you do in the recon determines how well the town does in the war against the sahuagin.
This would obviously work well in Q'barra. In addition to the lizardfolk plot, and the politics, there are a bunch of other Eberronesque elements (like sea princes, and the involvement of aquatic elves, and wars between aquatic races).
If I was to run it, I would probably add another layer. The sahuagin have actually been displaced by aboleths, and need bases that are partially on land to resist the push. Both the lizardfolk citadel and the town (which would have partially submerged ruins beneath it) qualify.