I wonder if the hatch that Eko and Locke discovered can be used?
If it truly does have cameras on all of the other hatches, then logically, it has a camera in the "Others" hatch. Of course, there are a couple logical possibilities screwing up this plan
A. The Others, long ago, removed all the cameras and they have known about the plane hatch for a while (Pearl). Perhaps they used it to spy on our well-known characters.
B. The Others are affiliated with Dharma, so there is not a camera in the hatch.
Basically, it seems likely there is no contact into their hatch from the outside (by camera), as I have to guess Eko or Locke would have wondered "who the hell are these people?" if they saw it.