So, after reading this thread, it seems to me that most of you guys here think that the only two reasons that such a game hasn't been made are because of money; it'd cost too much to make, and it wouldn't sell well enough.
It's too expensive to make, because that's an incredible amount of writing, mission construction, etc, that needs to be done to see it happen. There are effectively 8 paths through the game, and any combination thereof; if I made my character Selfish, Peaceable, Manipulative and Modest, that's going to play completely, totally differently than Selfless, Vicious, Plainspoken, and Modest. Even though they share extreme traits (Modesty in both cases), you're going to end up with ridiculously different outcomes. Which means lots of mission. Lots, and lots of missions. All with multiple outcomes. Even having 2 outcomes per mission may be insufficient. And then they'd have to chain together, to build a cohesive narratave. It's a massive undertaking as far as design and writing go. And that's on TOP of whatever other production costs there are.
The other inhibiting factor is that it wouldn't do well at retail. It's a (relatively) complex way to have game. You'd need a serious manual to go with, explaining how it all works, explaining the character and story. You wouldn't be able to easily throw up a tutorial section that takes not a second more than 15 minutes, and get the players going; doing however they choose in this world you've built for 'em. That means that a lot of players will skip over it; likely few who visit here, but try releasing this on the Wii? You'd never do serious revenue from that console and its audience.
So, it seems to me that we have a problem. Awesome, awesome game, and noone to make it. So... why not pitch this to Indie developers instead? This seems like the -perfect- game for an Indie PC developer. They aren't as hamstringed by the production costs for making vast worlds, because they don't have to draw and render a million, billion polygons with every game. Heaps of Indie games are two dimensional, or sprite-based. Which seems to me like a great way to do it. That, or have a procedural map-maker built into the game for random missions, which has been done before in professional games; it shouldn't be so difficult to port that over to 2D for a developer who's clever. Look at things like Nethack or Dwarf Fortress; in terms of procedural programming, they work well. So... with graphics out of the way as a time vampire, we can get to work.
Someone should definitely be working on this system. I'm likely going to be incorporating such ideas as moral-magnetism and multiple scales into the next DnD campaign I run; someone should surely make a game out of it.