I for one am not afraid to spoil the **** out of this (but hey, nobody's forcing anyone to highlight the white block below).
Per several spoiler videos of TOR on YouTube that can easily be found, it is clear that Revan's final fate is, after being put in stasis by the Sith Emperor for 300 years, he shows up in two quests, one for either side of the war and one chronologically taking place before the other. The first, the Republic one, has the players waking him up. The second, the Sith one, has you find him in some space station the details of which I don't care about, and because your party is Sith you fight, and you kill him. He dies quoting Darth Malak's final words before exploding in some energy burst thingy somewhat reminiscent of what happened when Palpatine died in RotJ (as well as a few other Jedi/Sith in the EU). Plenty of people want to ignore the narrative context of the scene and claim that he's still alive, but it's most likely that unless someone in charge of the stories does some serious bending-backward, it's the last we'll see of him.
There, now go write a fanfic that's better.