I love patrons. They offer so much story-telling potential and adventure hooks, but it helps to have mechanical support to make it feel more integrated in the game. I ran a five-year D&D campaign where I added MCDM's Strongholds and Followers, plus reputation rules based off an old ENworld article, and finally the need to have an instructor and spend coin to level up. I also had a modified alignment system. All of it helped make factions and patrons a central part of the game.
Currently, I'm running Warhammer Fantasy Role Play 4e. I haven't had to homebrew anything because I quite like their Between Adventures rules as written. They also include patron write ups in their adventures and splat books, including a book called Patrons of the Empire.
With my main group we run longer campaigns and patrons are a big part of making long campaigns work, in my experience.
