Hi, I am called Cable Hogue in those Deadlands- or Savage Worlds-Forums that I frequent.
I discovered Firefly when a longtime roleplaying friend of mine found those new episodes of a brand new series by Joss Whedon on the web. He did a download of the episodes that actually aired in the US TV and gave them to me to watch.
As a long time Babylon 5 fan, I honestly expected more Sci-Fi, more "seriousness" in my first viewing and so I was a bit disappointed by Firefly.
I frequently get to play "Deadlands: The weird West" roleplaying game, where Old West is mixed with steam tech, evil ghosts and magic. Quite a crossover setting. And not only in the 1870s, but also as "Deadlands: Hell on Earth" playing in a post-nuclear Mad-Max-like scorched earth setting and - as a conclusion to the vast Deadlands metaplot - in "Deadlands: Lost Colony" which is a human settled colony in space, cut from earth's supply, where the settlers have to make their future versus hostile aliens, even more hostile other humans and several supernatural baddies. It was after reading those Lost Colony books I took the Firefly DVDs and gave them another look. And this time it struck home.
We had played in the Traveller RPG since 1980 or so. There you often have a Free Trader spaceship, and take on sometimes legal jobs, sometimes not quite legal mission to "keep flying". - Sounds familiar? - It should.
This is the spirit of the whole Firefly series. It is those "keep her flying", "no power in the 'verse can stop me" and so on, that makes the Firefly feeling. And I like it.
In fact, as I know the Savage Worlds generic Fast!Furious!Fun!-RPG system well enough to take a conversion of the Firefly setting for this RPG rules set, we've played in the Firefly 'Verse just to see, whether we would be able to experience the Firefly feeling. - And it works!
We will continue to play Savage Firefly and have recently thought about converting several old Traveller adventures into the Firefly 'Verse. I am confident, that this will work out shiny.