I was just watching a video of the playbook on Engadget where it was being linked up with a white Torch beside it and I realized that there seemed to be two notification lights side by side each other on the white Torch that they were using. Was I seeing things....??
That is indeed the proximity sensor, The Torch is a bit different in that instead of having the proximity/ambient light sensor built into the LED, it's been put into a separate little spot of it's own. It's actually almost the same with the (currently MIA) white iPhone 4...
If you have a really bright flashlight on hand, You can actually shine it in the same spot on a black Torch, and you'll just barely be able to make out the second circular hole where the sensors are, as everyone has said, it's just far easier to see on the white models.