Rules needed to be tweaked obviously. Neither town nor scum should be able to win and end the game. To give players some feeling of archivement, they'd gain points though:
Having taken part in the lynch of x members = points
Staying alive for x rounds = more points
Having successfully used their ability (not sure about this, hard to quantify) = even more points
Staying alive for x rounds = a certain amount of points
They can even participate more than once in the game, even if they were killed. To avoid confusion, they should only be allowed to re-enter if the whole of the players they have played with has been revolved, so no player would mistake the reentered player with his former role.
Once a player dies, another one would immediately enter the game with a role that would balance the current mix of roles available.
So, what if town hits a number of scum and just lynches every player entering the game? Frankly I don't know yet. I am open for your valuable suggestions though.
I am still working on the details, especially the game mechanics, but I think it could be archived.
What do you think? Am I making sense here? I am really interested in you opinions. Question is, would you be interested in the game?