If race and class were tangible social constructs in a setting

[Dangerious P. Cats]

For a while now I've had an idea for a setting where society collapses and the only people to survive are are re-enactors and role-players. While the re-enactors are off deviding themselves up between kingdoms of the SCA and metal weapons groups the roleplayers who survive build their society as though it were a roleplaying game (a very particular roleplaying game) and so devide everyone within the society is given a race, class and level. I'm trying to work out how this affects people socially. What insitutions would be formed around class and how would being a level 12 farmer be better for you than being a level 7 farmer? Also I'm trying to work out what classes might need to evolve to make such a society work? You need to have craftsmen, farmers beuracrats to keep a society going, and since everything in the society needs to have a class you need to have classes for them (people without a race/class/level are deemed to be a "monster" and have no rights in the society).