simonh said:
...I don't see significant scope for a spinoff series. Any new production would be very different from the original.
What about the whole war prior to the series? Just (or focused on) Mal and Zoe. We only need to get two of the original cast back (possibly even just one, Nathan Fillion) but with room for cameos for (most if not all of) the others if desired. And being a straight up car chases... er space battles and exploding action with guns it should be an easy sell to the studios (we'll slip in the story and plot bits when they aren't looking

)
No Serenity (that might even be a catchy title for it) though I can easily see working in a cameo, even recurring, for it too. I've long felt it was previously a troop carrier and one reason Mal insisted on it as his Trader was past favorable experience with the class (maybe even Serenity herself) during the war. He knew just how much heart and soul the ship had. No flash, just lots of strength, unlike the other ships on the lot the day he bought it.