Just a little update for everyone. From my testing it seems that the best way to get the desired effect is to change your enviroment tab all the way to white. Now normally this will overexpose your materials, so to counteract this turn down the diffuse on your materials to somewhere around .4 to get a normal looking outcome.

In order to get an image plane underneath that looks white, but isnt too overexposed to pick up shadows, make a poly plane and apply a brand new blank lambert shader. You don't have to change anything except putting the diffuse down to .630. The only thing left is adding a directional light (turned downed the intensity to about .1) and turn on final gather.

Here's a quick example of what I've been able to get. I think it's pretty close.