I played a neat rpg called Hands of War, and it worked like this.
There were 7 factions.
Light versus Darkness
Rangers versus Warriors versus Magicians
Merchants versus Bandits
The idea was that for each quest you took that pertained to Light v Darkness, you would gain +2 or so loyalty to light, while -2 to darkness (I'm EXTREMELY sorry if this is already suggested somewhere).
The chart worked like this
Kill on Sight---Unfriendly---Neutral---Friendly---Allies
You normally started on Neutral, which contained 1000 points. If you hit the bottom or top of the Neutral zone, you'd hit Friendly/Unfriendly. From there, there are 3000 points of rep needed to hit Allies or Kill on Sight. Killing someone from Light faction brings Darkness rep down, and completing a light quest brings darkness loyalty down almost 50 points at once, depending on the size of the quest.
The reason I'm suggesting this is because I think that we could build a ranking system that specifically denotes just how far you've gone against a faction.