Re: Eberron 3.5 or Pathfinder
The only way I see such a thing working, is if you have a group of friends, to play the other PC's, and you all make characters that have known one another long before the game starts, and that all share similar goals. a 100% team oriented game is vastly hard to do, because you other get bogged down in debates about what to do next (person A wants to go slay the Dragon, Person B wants to attend the Ball, Person C wants to go to a council meeting.), OR, you will have a majority Rules set up, where it is whoever has the most votes decides what to do, again, similar to your 'FF Sidekick' Comment.
IF you can find someone, I would be willing to give it a try, but I like social intrigue, and a party based social game, unless it is something like GoT where your all members of the same house and fighting for the same goal, is hard to pull off.