Multiple Characters and Storylines

The concept is having the players be able to play different characters that have different stories yet all accomplish the same goal.

I've been tinkering with the idea of this for a while and been doing some research on how would be the best way to implement this.

Some games I'm looking at are Saga Frontier and Heavy Rain.  Also, looking at Game of Thrones (books and show) and Watchman (graphics novel).

What would be some good sources to look at that implement this well?

These guys are some buddies of mine, has something similar to what you're discussing http://www.ekuatorgames.com/

Thanks for posting this!  Downloading demo to check out their progress.

Seiken Densetsu 3 is a prime example of this.

Suikoden III. :)