Dawn of the Scarlet Sun is set in Magnimar, and if i remember correctly was written for a group of 6 PCs of 5th level. It's a free download.
You may need to tone it down, i heard the bbeg of the module may induce a tpk to ill prepared groups.
SPOILERS RotR and Dawn of the Scarlet Sun.:
To fit it in the story: Have Justice Ironbriar set the whole thing up - on the one hand he is a Justice and as such may have an 'official' interest in keeping the city save. On the other hand his cult of norgorber (and behind all that xanesha) may have beef with this shax cleric moving in their turf and reaping in their harvest – question is: how greedy can sarenrae clerics be to be a target for the skinsaws? Get creative ;)
