Although I consider my gaming tastes to lean towards the dark end of things, I also really like swashbucklers, and my settings tend to have more of a swashbuckler feel than a traditional fantasy feel. I'd rather have D'Artagnan than an traditionalist Arthurian knight, for instance. I think a lot of the original sword & sorcery foundational literature also has a similar feel; Conan, Fafhrd, the Gray Mouser, etc.--they're essentially swashbucklers, moving through an occasionally fairly dark setting. In fact, I privately suspect that the adventure novels of guys like Sabatini must have been an influence on a lot of the pulp writers, and not just in sword & sorcery. As were the often swashbuckling tales of the Arabian Nights, and other occasionally picaresque works that all are part of the melange that led to the formation of the sword & sorcery genre.
Of course, by throwing in a large sea into my setting, and having vaguely "Arabian Nights" esque major powers like Qizmir, I've often subconsciously paved the way for a similar feel myself. My Qizmiri colonists; those that come through the Strait and into the Mezzovian Sea itself, are the most adventurous, frontiersmen types. They're not noble. They're not royalty. They're not disciplined soldiers. They're basically Barbary pirates. The Terrasan Empire itself is decadent and weak; breakaway statelets like Porto Liure are not at all unlike Green Ronin's Freeport in most respects.
All in all, I've generated an environment that's much more friendly, I believe, to the swashbuckler than to the "traditional" fantasy tale. How exactly do swashbucklers and dark fantasy cum horror go together? That's a little bit trickier. A few works of media have attempted to combine them in very iconic ways, such as Stephen Sommers' Van Helsing. Then again, that movie isn't really very good, is it? Sommers had better luck with his earlier The Mummy, and in fact Brendan Frasier was described by Sommers as having that perfect Errol Flynn swashbuckling type character. You can't get more authoritatively swashbucklerish than Errol Flynn.
So; it's a tricky line to walk. I'm not sure exactly how well I walk it, but even my failures to stay correctly in tone, or whatever, tend to be entertaining, so I'm not sweating it too much. Also; whew! It's exhausting to hotlink stuff in my posts that intensively. It's an experiment, though. I'm trying to do more of it, but we'll see how well it turns out.