While I agree with everbody else that it won't happen, I don't think this is the answer you are looking for.
We would have an extremely quick, yet short backcourt. This wouldn't be horrible defensively, except in the post where we would need help defense. Offensively, it would be a thing of beauty. I liked what I saw with Rondo and West (and very much hope West sticks around) and CP3 is 10X the player West is. As long as the big 3 and other 'finishers' stay around, we would have players tripping over themselves all over the place.
This just isn't something that really happens successfully, though. There are teams that have won championship with two shooting guards, but I don't know of any that have had two definite PGs.