I first started thinking about this idea quite a while back, when the first Survivor TV shows aired. My first ideas were centered around a structured play-by-email game with computer moderation, and a formal win / lose element. I was also watching some expedition racing events, and combining the two seemed like something of a natural fit. The first cut rules were pretty complex, with each player running a team of characters through a physically hazardous wilderness. Teams would have to pass various checkpoints, some of which featured challenges and obstacles of their own. The idea was interesting, but never really jelled into anything playable.
The second incarnation of this idea centered around a traditional RPG played as a survival game. The original scenario I envisioned was a shipwrecked collection of passengers on a deserted island--sounds familiar right? Stupid TV, stealing my ideas! I toyed around with this idea a bit, trying to develop it enough to turn it into a playable one-shot game, but never got far enough with it to actually run the game. While I was working on this I think I was sticking pretty closely to the idea of a cooperative party game, and I'm not sure the survival game I have in mind really fits that model.
Now I'm toying with the whole idea again and have gone back to a more conflict oriented game, with actual winners (survivors) and losers (non-survivors) coupled to a RPG-like rule-set. One of the problems, I think, is developing a resolution system that provides mechanical benefits and consequences to both social and physical conflict or cooperation. I've been thinking about a two-sided stress system, with both mental and physical tracks, coupled with an attribute / skill mechanic. Physical stress affects attributes, mental stress affects skills, including interpersonal skills.
Mechanically it would require differentiation of pure attribute abilities from learned skills. Running from the wild boar that's trying to gore you might be a pure attribute check of brawn, affected by physical stress. Trying to stitch up a wound with needle and thread might be a skill based check affected by mental stress. I'm not sure about how cleanly this divide can be made, perhaps some actions are combined attribute / skill checks, perhaps stress gets applied to individual attributes or skills. I dunno.
I've also been thinking about using a random island generator, along with random encounter / resource generation, to build the setting on the fly. Players have to spend time exploring to uncover food and water sources, harvest materials to create shelter, and cooperate or compete to find a way off the island. An element of randomness seems fitting in a survival-type game, a genre that needs a certain amount of life-threatening tension to really work.
Like I said in the beginning, this is all pretty nebulous, but at least now it's written down. It could be I'm reinventing the wheel here and some kind reader will suggest a game that does exactly what I'm trying to do.