The problem with this is that the user will be presented a giant list of several hundred friends, which is intimidating to say the least. (Facebook hasn't really tried to discourage indiscriminate friending, preferring instead to algorithmically filter what it shows you in your feed, with the result that most users have ended up with an out-of-control friend list.)

There's one and only one way to make this work with an already existing social graph: show the user a clustered view of their friends. To see examples, do an image search for 'vizster'. http://vis.stanford.edu/papers/vizster